Image processing apparatus and method, and image pickup apparatus

[0001] The present invention relates to an image processing device and method, and an image-taking device, and particularly relates to an image processing device and method, and an image-taking device, which take into consideration difference between signals detected by sensors and the real world.

[0002] One type of processing for generating images with higher resolution based on input images, is class classification adaptation processing. An example of class classification adaptation processing is processing wherein coefficients used in processing for generating images with higher resolution are generated beforehand, in the spatial direction, and images are generated with higher resolution in the spatial direction based on the generated coefficients.

[0003] FIG. 1 is a block diagram illustrating the configuration of a conventional image processing device for generating coefficients used in class classification adaptation processing for generating HD (High Definition) images from SD (Standard Definition) images.

[0004] Frame memory 11 stores input images, which are HD images, in increments of frames. The frame memory 11 supplies the stored HD images to a weighted averaging unit 12 and a corresponding pixel obtaining unit 16.

[0005] The weighted averaging unit 12 performs ¼ weighted averaging on the HD images stored in the frame memory 11, generates SD images, and supplies the generated SD images to the frame memory 13.

[0006] The frame memory 13 stores the SD images supplied from the weighted averaging unit 12 in increments of frames, and supplies the stored SD images to a class classification unit 14 and prediction tap obtaining unit 15.

[0007] The class classification unit 14 is configured of a class tap obtaining unit 21 and a waveform classification unit 22, and performs class classification of pixels of interest which are the pixel of interest in the SD images stored in the frame memory 13. The class tap obtaining unit 21 obtains a predetermined number of class taps which are pixels of the SD image corresponding to the pixel of interest from the frame memory 13, and supplies the obtained class taps to the waveform classification unit 22.

[0008] FIG. 2 is a diagram explaining the class taps obtained by the class tap obtaining unit 21. As shown in FIG. 2, the class tap obtaining unit 21 obtains eleven class taps at predetermined positions.

[0009] The waveform classification unit 22 classifies the pixel of interest into one class out of multiple classes, based on the class taps, and supplies a class No. corresponding to the classified class, to the prediction tap obtaining unit 15. The waveform classification unit 22 classifies the pixel of interest into one class out of 2048 classes, based on the eleven class taps.

[0010] The prediction tap obtaining unit 15 obtains a predetermined number of prediction taps which are pixels of the SD image, corresponding to the classified class from the frame memory 13, based on the class No., and supplies the obtained prediction taps and class Nos. to a corresponding pixel obtaining unit 16.

[0011] FIG. 3 is a diagram explaining prediction taps which the prediction tap obtaining unit 15 obtains. As shown in FIG. 3, the prediction tap obtaining unit 15 obtains nine prediction taps at predetermined locations.

[0012] The corresponding pixel obtaining unit 16 obtains, from the frame memory 11, pixels of the HD image corresponding to the pixel values to be predicted, based on the prediction taps and the class Nos., and supplies the prediction taps, class Nos., and the pixels of the HD image corresponding to the obtained pixel values to be predicted, to a normal equation generating unit 17.

[0013] The normal equation generating unit 17 generates normal equations corresponding to relationships between prediction taps and pixel values to be predicted, corresponding to the classes, based on the prediction taps, class Nos., and the obtained pixel values to be predicted, and supplies the generated normal equations corresponding to the classes, to a coefficient calculating unit 18.

[0014] The coefficient calculating unit 18 solves the normal equation supplied from the normal equation generating unit 17, calculates coefficient sets corresponding to each class, and supplies the calculated coefficient sets to coefficient set memory 19, along with the class Nos.

[0015] The coefficient set memory 19 stores the calculated coefficient sets corresponding to the classes, based on the class Nos.

[0016] FIG. 4 is a diagram explaining an overview of class classification adaptation processing. In class classification adaptation processing, a tutor image which is an HD image is used to generate a corresponding SD image, by ¼ weighted average processing. The generated SD image is called a student image.

[0017] Next, a coefficient set for generating an HD image from the SD image is generated, based on the tutor image which is the HD image and the student image which is the corresponding SD image. The coefficient set is configured of coefficients for generating an HD image from an SD image, by linear prediction and the like.

[0018] A quadruple-density image is generated from the coefficients set thus generated and the SD image, by linear prediction and the like. The processing for generating an image or the like with higher density, from a coefficient set and an input image, is also called mapping.

[0019] SNR comparison, or visual qualitative evaluation is performed, based on the generated quadruple-density image and a corresponding HD image.

[0020] A coefficient set generated from a particular tutor image and corresponding student image is called a self coefficient set of the particular tutor image and corresponding student image. Mapping using the self coefficient set is called self mapping. A coefficient set generated from multiple other tutor images and corresponding student images is called a cross coefficient set.

[0021] On the other hand, with images obtained by a video camera taking a foreground subject which moves across a predetermined stationary background, movement blurring occurs in the event that the speed of movement of the object is relatively fast, and mixing of the foreground and background occurs.

[0022] With conventional class classification adaptation processing, one set of coefficients is generated for all of the foreground, background, and portions where mixing between the foreground and background occurs, by learning processing such as described above, and mapping processing is executed based on the coefficient set.

[0023] The conventional learning processing for generating coefficients used in the processing for generating HD images from SD images will be described, with reference to the flowchart shown in FIG. 6. In Step S11, an image processing device judges whether or not there are unprocessed pixels in the student image, and in the event that judgment is made that there are unprocessed pixels in the student image, the flow proceeds to Step S12, and pixels of interest are obtained from the student image, in order of raster scan.

[0024] In Step S13, the class tap obtaining unit 21 of the class classification unit 14 obtains a class tap corresponding to the pixel of interest, from the student image stored in the frame memory 13. In Step S14, the waveform classification unit 22 of the class classification unit 14 performs class classification of the pixel of interest, based on the class tap. In Step S15, the prediction tap obtaining unit 15 obtains a prediction tap corresponding to the pixel of interest from the student image stored in the frame memory 13, based on the class into which classification has been made.

[0025] In Step S16, the corresponding pixel obtaining unit 16 obtains a pixel corresponding to a pixel value to be predicted, from tutor data stored in the frame memory 11, based on the class into which classification has been made.

[0026] In Step S17, the normal equation generating unit 17 adds a pixel value of a pixel corresponding to the prediction tap and pixel value to be predicted to the matrix for each class, based on the class into which classification has been made, the flow returns to Step S11, and the image processing device repeats judgment regarding whether or not there are unprocessed pixels. The matrixes for each class to which the pixel value of a pixel corresponding to the prediction tap and pixel value to be predicted are added, correspond to the normal equation for calculating coefficients for each class.

[0027] In the event that judgment is made in Step S11 that there are no unprocessed pixels in the student image, the flow proceeds to Step S18, wherein the normal equation generating unit 17 supplies the matrix for each class wherein a pixel value of a pixel corresponding to the prediction tap and pixel value to be predicted has been set, to the coefficient calculating unit 18. The coefficient calculating unit 18 solves the matrix for each class wherein a pixel value of a pixel corresponding to the prediction tap and pixel value to be predicted has been set, and calculates a coefficient set for each class.

[0028] In Step S19, the coefficient calculating unit 18 outputs the coefficient for each class that has been calculated, to the coefficient set memory 19. The coefficient set memory 19 stores a coefficient set for each class, and the processing ends.

[0029] FIG. 7 is a block diagram illustrating the configuration of a conventional image processing device for generating HD images from SD images, by class classification adaptation processing.

[0030] Frame memory 31 stores input images which are SD images, in increments of frames. The frame memory 31 supplies the stored SD images to a mapping unit 32.

[0031] The SD images input to the mapping unit 32 are supplied to a class classification unit 41 and a prediction tap obtaining unit 42.

[0032] The class classification unit 41 is configured of a class tap obtaining unit 51 and a waveform classification unit 52, and performs class classification of pixels of interest which are the pixel of interest in the SD images stored in the frame memory 31. The class tap obtaining unit 51 obtains from the frame memory 31 a predetermined number of class taps corresponding to the pixel of interest, and supplies the obtained class taps to the waveform classification unit 52.

[0033] The waveform classification unit 52 classifies the pixel of interest into one class out of multiple classes, based on the class taps, and supplies a class No. corresponding to the classified class, to the prediction tap obtaining unit 42.

[0034] The prediction tap obtaining unit 42 obtains from the input image stored in the frame memory 31 a predetermined number of prediction taps corresponding to the classified class, based on the class No., and supplies the obtained prediction taps and class Nos. to a prediction computation unit 43.

[0035] The prediction computation unit 43 obtains coefficient sets corresponding to classes from the coefficient sets stored in coefficient set memory 33, based on the class No. The prediction computation unit 43 predicts pixel values of predicted images by linear prediction, based on coefficient sets corresponding to classes, and prediction taps. The prediction computation unit 43 supplies the predicted pixel values to frame memory 34.

[0036] The frame memory 34 stores-predicted pixel values supplied from the prediction computation unit 43, and outputs an HD image wherein the predicted pixel values have been set.

[0037] FIG. 8 is a diagram illustrating the pixel values of the input image, and the pixel values of the output image generated by class classification adaptation processing. In FIG. 8, the white squares indicate input signals, and the solid circles indicate output signals. As shown in FIG. 8, the image generated by the class classification adaptation processing contains waveforms lost in the bandwidth restriction of the SD image. In this sense, it can be said that processing for generating an image with higher resolution by the class classification adaptation processing creates resolution.

[0038] The conventional processing for creating images, for generating HD images from SD image with an image processing device which executes processing for creating resolution by class classification adaptation processing, will be described with reference to the flowchart in FIG. 9.

[0039] In Step S31, the image processing device judges whether or not there are unprocessed pixels in the input image, and in the event that judgment is made that there are unprocessed pixels in the input image, the flow proceeds to Step S32, where the mapping unit 32 obtains a coefficient set stored in the coefficient set memory 33. In Step S33, the image processing device obtains pixels of interest from the input image in raster scan order.

[0040] In Step S34, the class tap obtaining unit 51 of the class classification unit 41 obtains a class tap corresponding to the pixel of interest, from the input image stored in the frame memory 31. In Step S35, the waveform classification unit 52 of the class classification unit 41 performs class classification of the pixel of interest into one class, based on the class tap.

[0041] In Step S36, the prediction tap obtaining unit 42 obtains a prediction tap corresponding to the pixel of interest from the input image stored in the frame memory 31, based on the class into which classification has been made.

[0042] In Step S37, the prediction computation unit 43 obtains a pixel value of a predicted image by linear prediction, based on the coefficient set corresponding to the class into which classification has been made, and the prediction tap.

[0043] In Step S38, the prediction computation unit 43 outputs the predicted pixel value to the frame memory 34. The frame memory 34 stores the pixel value supplied from the prediction computation unit 43. The procedures return to Step S31, and repeats judgement regarding whether or not there are unprocessed pixels.

[0044] In the event that judgment is made in Step S31 that there are no unprocessed pixels in an input image, the flow proceeds to Step S39, where the frame memory 34 outputs the stored predicted image wherein predicted values are set, and the processing ends.

[0045] Also, edge enhancing processing is used for converting the input image into an image with the sense-of-resolution enhanced even further. As with the class classification adaptation processing described above, the same processing is executed for the entire screen with the edge enhancement processing as well.

[0046] However, in the event that objects move in front of still backgrounds, movement blurring occurs not only due to mixture of the moving object images itself, but also due to mixture of the moving object images and the background images. Conventionally, processing images corresponding to the mixing of the background image and the image of the moving object had not been given thought.

[0047] The present invention has been made in light of the above, and it is an object thereof to enable processing of images corresponding to the mixing of background images and images of the moving objects.

[0048] An image processing device according to the present invention comprises: region specifying means for specifying, based on the input image data, one or the other of a mixed region made up of a mixture of a foreground object component configuring foreground objects and a background object component configuring background objects, and a non-mixed region made up of one of a foreground region made up of the foreground object component and a background region made up of a background object component configuring the background objects, and outputting region specifying information corresponding to the results of specifying; separating means for separating the input image data in at least the mixed region into the foreground object component and the background object component, corresponding to the region specifying information; and processing means for individually processing the foreground object component and the background object component, corresponding to the results of separation.

[0049] The image processing device may further comprise removing means for removing movement blurring of at least one of the foreground object component and the background object component, with the processing means individually processing the foreground object component and the background object component which have been subjected to movement blurring removal.

[0050] The region specifying means may further specify a covered background region and an uncovered background region, and output the region specifying information corresponding to the results of specifying, with the separating means separating the input image data into the foreground object component and the background object component in the covered background region and the uncovered background region.

[0051] The processing means may generate coefficients used for class classification adaptation processing, for each of the foreground object component and the background object component.

[0052] The processing means may generate output image data for each of the foreground object component and the background object component, by class classification adaptation processing.

[0053] The processing means may perform edge enhancement for each of the foreground object component and the background object component.

[0054] The image processing device may further comprise: foreground component image generating means for generating a foreground component image by synthesizing the foreground object component separated in the mixed region and the pixel data of the foreground region; and background component image generating means for generating a background component image by synthesizing the background object component separated in the mixed region and the pixel data of the background region; with the processing means individually processing the foreground component image and the background component image which are generated.

[0055] An image processing method according to the present invention comprises: a region specifying step for specifying, based on the input image data, one or the other of a mixed region made up of a mixture of a foreground object component configuring foreground objects and a background object component configuring background objects, and a non-mixed region made up of one of a foreground region made up of the foreground object component and a background region made up of a background object component configuring the background objects, and outputting region specifying information corresponding to the results of specifying; a separating step for separating the input image data in at least the mixed region into the foreground object component and the background object component, corresponding to the region specifying information; and a processing step for individually processing the foreground object component and the background object component, corresponding to the results of separation.

[0056] The image processing method may further comprise a removing step for removing movement blurring of at least one of the foreground object component and the background object component, with the foreground object component and the background object component which have been subjected to movement blurring removal being individually processed in the processing step.

[0057] In the region specifying step, a covered background region and an uncovered background region may be further specified, and the region specifying information corresponding to the results of specifying output, with the input image data being separated into the foreground object component and the background object component in the covered background region and the uncovered background region in the separating step.

[0058] In the processing step, coefficients used for class classification adaptation processing may be generated, for each of the foreground object component and the background object component.

[0059] In the processing step, output image data may be generated for each of the foreground object component and the background object component, by class classification adaptation processing.

[0060] In the processing step, edge enhancement may be performed for each of the foreground object component and the background object component.

[0061] The image processing method may further comprise: a foreground component image generating step for generating a foreground component image by synthesizing the foreground object component separated in the mixed region and the pixel data of the foreground region; and a background component image generating step for generating a background component image by synthesizing the background object component separated in the mixed region and the pixel data of the background region; with the foreground component image and the background component image which are generated, being individually processed in the processing step.

[0062] A program in a recording medium according to the present invention comprises: a region specifying step for specifying, based on the input image data, one or the other of a mixed region made up of a mixture of a foreground object component configuring foreground objects and a background object component configuring background objects, and a non-mixed region made up of one of a foreground region made up of the foreground object component and a background region made up of a background object component configuring the background objects, and outputting region specifying information corresponding to the results of specifying; a separating step for separating the input image data in at least the mixed region into the foreground object component and the background object component, corresponding to the region specifying information; and a processing step for individually processing the foreground object component and the background object component, corresponding to the results of separation.

[0063] The program in the recording medium may further comprise a removing step for removing movement blurring of at least one of the foreground object component and the background object component, with the foreground object component and the background object component which have been subjected to movement blurring removal being individually processed in the processing step.

[0064] In the region specifying step, a covered background region and an uncovered background region may be further specified, and the region specifying information corresponding to the results of specifying output, with the input image data being separated into the foreground object component and the background object component in the covered background region and the uncovered background region in the separating step.

[0065] In the processing step, coefficients used for class classification adaptation processing may be generated, for each of the foreground object component and the background object component.

[0066] In the processing step, output image data may be generated for each of the foreground object component and the background object component, by class classification adaptation processing.

[0067] In the processing step, edge enhancement may be performed for each of the foreground object component and the background object component.

[0068] The program in the recording medium may further comprise: a foreground component image generating step for generating a foreground component image by synthesizing the foreground object component separated in the mixed region and the pixel data of the foreground region; and a background component image generating step for generating a background component image by synthesizing the background object component separated in the mixed region and the pixel data of the background region; with the foreground component image and the background component image which are generated, being individually processed in the processing step.

[0069] A program according to the present invention causes a computer to execute: a region specifying step for specifying, based on the input image data, one or the other of a mixed region made up of a mixture of a foreground object component configuring foreground objects and a background object component configuring background objects, and a non-mixed region made up of one of a foreground region made up of the foreground object component and a background region made up of a background object component configuring the background objects, and outputting region specifying information corresponding to the results of specifying; a separating step for separating the input image data in at least the mixed region into the foreground object component and the background object component, corresponding to the region specifying information; and a processing step for individually processing the foreground object component and the background object component, corresponding to the results of separation.

[0070] The program may further comprise a removing step for removing movement blurring of at least one of the foreground object component and the background object component, with the foreground object component and the background object component which have been subjected to movement blurring removal being individually processed in the processing step.

[0071] In the region specifying step, a covered background region and an uncovered background region may be further specified, and the region specifying information corresponding to the results of specifying output, with the input image data being separated into the foreground object component and the background object component in the covered background region and the uncovered background region in the separating step.

[0072] In the processing step, coefficients used for class classification adaptation processing may be generated, for each of the foreground object component and the background object component.

[0073] In the processing step, output image data may be generated for each of the foreground object component and the background object component, by class classification adaptation processing.

[0074] In the processing step, edge enhancement may be performed for each of the foreground object component and the background object component.

[0075] The program may further comprise: a foreground component image generating step for generating a foreground component image by synthesizing the foreground object component separated in the mixed region and the pixel data of the foreground region; and a background component image generating step for generating a background component image by synthesizing the background object component separated in the mixed region and the pixel data of the background region; with the foreground component image and the background component image which are generated, being individually processed in the processing step.

[0076] An image-taking device according to the present invention comprises: image-taking means for outputting a subject image taken by an image-taking device having a predetermined number of pixels having time-integration effects as taken image data made up of a predetermined number of pieces of pixel data; region specifying means for specifying, based on the taken image data, one or the other of a mixed region made up of a mixture of a foreground object component configuring foreground objects and a background object component configuring background objects, and a non-mixed region made up of one of a foreground region made up of the foreground object component and a background region made up of a background object component configuring the background objects, and outputting region specifying information corresponding to the results of specifying; separating means for separating the taken image data in at least the mixed region into the foreground object component and the background object component, corresponding to the region specifying information; and processing means for individually processing the foreground object component and the background object component, corresponding to the results of separation.

[0077] The image-taking device may further comprise removing means for removing movement blurring of at least one of the foreground object component and the background object component, with the processing means individually processing the foreground object component and the background object component which have been subjected to movement blurring removal.

[0078] The region specifying means may further specify a covered background region and an uncovered background region, and output the region specifying information corresponding to the results of specifying, with the separating means separating the taken image data into the foreground object component and the background object component in the covered background region and the uncovered background region.

[0079] The processing means may generate coefficients used for class classification adaptation processing, for each of the foreground object component and the background object component.

[0080] The processing means may generate output image data for each of the foreground object component and the background object component, by class classification adaptation processing.

[0081] The processing means may perform edge enhancement for each of the foreground object component and the background object component.

[0082] The image-taking device may further comprise: foreground component image generating means for generating a foreground component image by synthesizing the foreground object component separated in the mixed region and the pixel data of the foreground region; and background component image generating means for generating a background component image by synthesizing the background object component separated in the mixed region and the pixel data of the background region, with the processing means individually processing the foreground component image and the background component image which are generated.

[0083] One or the other of a mixed region made up of a mixture of a foreground object component configuring foreground objects and a background object component configuring background objects, and a non-mixed region made up of one of a foreground region made up of the foreground object component and a background region made up of a background object component configuring the background objects, are specified, region specifying information corresponding to the results of specifying is output, the input image data in at least the mixed region is separated into the foreground object component and the background object component, corresponding to the region specifying information, and the foreground object component and the background object component are individually processed, corresponding to the results of separation.

[0084] Thus, in the event that a moving object is photographed, for example, images can be processed corresponding to the mixing of background images and moving object images.

[0259] FIG. 10 is a block diagram which illustrates the configuration of an embodiment of the image processing device according to the present invention. A CPU (Central Processing Unit) 71 performs various types of processing following programs stored in ROM (Read Only Memory) 72, or a storage unit 78. RAM (Random Access Memory) 73 suitably stores programs for the CPU 71 to execute, data, and so forth. These CPU 71, ROM 72, and RAM 73 are mutually connected via a bus 74.

[0260] The CPU 71 is also connected to an input/output interface 75 via the bus 74. The input/output interface 75 is connected to an input unit 76 such as a keyboard, mouse, microphone, or the like, and is connected to an output unit 77 such as a display, speaker, or the like. The CPU 71 performs various types of processing corresponding to instructions input from the input unit 76. The CPU 71 then outputs images, audio, or the like, which are obtained as a result of processing, to the output unit 77.

[0261] The storage unit 78 connected to the input/output interface 75 comprises a hard disk, for example, and stores programs for the CPU 71 to execute and various types of data. A communication unit 79 communicates with external devices via the Internet or other networks. In this case of the example, the communication unit 79 serves as an obtaining unit which obtains output from a sensor.

[0262] Also, an arrangement may be made wherein programs are obtained via the communication unit 79, and are stored in the storage unit 78.

[0263] A drive 80 connected to the input/output interface 75 drives a magnetic disk 91, optical disk 92, magneto-optical disk 93, semiconductor memory 94, or the like, in the event that those are mounted thereon, and obtains programs and data stored therein. The obtained programs and data are transmitted to the storage unit 78 and stored therein, as necessary.

[0264] FIG. 11 is a block diagram which illustrates the configuration of the functions of the image processing device according to the present invention.

[0265] Note that whether each function of the image processing device is realized by hardware or software does not matter. That is to say, each block diagram in the present Specification may be regarded as not only a hardware block diagram but also as a software function block diagram.

[0266] Here, the input image input in the image processing device contains movement blurring.

[0267] The movement blurring means distortion which is included in images corresponding to moving objects, which occurs due to movement of objects which are objects of image-taking in the real world and due to image-taking properties of the sensor.

[0268] In the present Specification, images corresponding to objects which are objects of image-taking in the real world are called image objects.

[0269] Input images provided to the image processing device are provided to an object extracting unit 101, a region specifying unit 103, a mixture ratio calculating unit 104, and a foreground/background separation unit 105.

[0270] The object extracting unit 101 roughly extracts the image objects corresponding to the foreground object contained in the input image, and supplies the extracted image object to the movement detecting unit 102. The object extracting unit 101 roughly extracts the image object corresponding to the foreground object, for example, by detecting the outlines of the image object corresponding to the foreground object contained in input image.

[0271] The object extracting unit 101 roughly extracts the image object corresponding to the background object contained in the input image, and supplies the extracted image object to the movement detecting unit 102. The object extracting unit 101 roughly extracts the image object corresponding to the background object, by the difference between the input image and the image object corresponding to the extracted foreground object, for example.

[0272] Also, for example, an arrangement may be made wherein the object extracting unit 101 roughly extracts the image objects corresponding to the foreground objects and the image objects corresponding to the background objects based upon the difference between the background images stored in background memory provided therein and the input images.

[0273] The movement detecting unit 102 calculates the movement vectors of the image object corresponding to the roughly extracted foreground objects by techniques such as block matching, gradation, phase correlation, pixel recursion, or the like, and supplies the calculated movement vectors and movement vector position information (information for specifying the pixel positions corresponding to the movement vectors) to the region specifying unit 103.

[0274] The movement vector output from the movement detecting unit 102 includes information corresponding to a movement amount v.

[0275] Also, for example, an arrangement may be made wherein the movement detecting unit 102 outputs the movement vector per image object to the movement blurring adjustment unit 106 along with the pixel position information for specifying a pixel of the image object.

[0276] The movement amount v is a value which represents the change of position of the image corresponding to the moving object in increments of pixel interval. For example, in the event that the object image corresponding to the foreground moves so as to be displayed at a position four pixels away in the following frame with a given frame as a reference, the movement amount v of the image of the object corresponding to the foreground is 4.

[0277] The region specifying unit 103 classifies each pixel of the input image into one of the foreground region, the background region, or the mixed region which consists of the uncovered background region and the covered background region, and supplies the information which indicates which of the foreground region, the background region, or the mixed region which consists of the uncovered background region or the covered background region, each pixel belongs to, (which will be referred to as region information hereafter), to the mixture ratio calculation unit 104 and the foreground/background separation unit 105. Note that details of the mixed region, uncovered background region, and the covered background region will be described later.

[0278] The mixture ratio calculating unit 104 calculates the mixture ratio corresponding to the pixels contained in the mixed region (which will be referred to as mixture ratio α hereafter) based upon the input image and the region information supplied from the region specifying unit 103, and supplies the calculated mixed ratio to the foreground/background separating unit 105.

[0279] The mixture ratio α is a value which represents the ratio of the image component corresponding to the background object (which will also be referred to as background component hereafter) with the pixel value as indicated in Expression (3) described below.

[0280] The foreground/background separation unit 105 separates the image components corresponding to the foreground object (which will be also referred to as the foreground component hereafter) and the background component image which consists of only the background components based upon the region information supplied from the region specifying unit 103 and the mixture ratio α supplied from the mixture ratio calculation unit 104, and supplies the image in the background region, the image which consists of only the background components in the uncovered background region (which will be referred to as the background component image in the uncovered background region), the image which consists of only the foreground components in the uncovered background region (which will be referred to as the foreground component image in the uncovered background region), the image which consists of only the background components in the covered background region (which will be referred to as the background component image in the covered background region), the image which consists of only the foreground components in the covered background region (which will be referred to as the foreground component image in the covered background region), and the image in the foreground region, to the separated image processing unit 106.

[0281] The separated image processing unit 106 performs processing for the image in the background region, the background component image in the uncovered background region, the foreground component image in the uncovered background region, the background component image in the covered background region, the foreground component image in the covered background region, and the image in the foreground region, supplied from the foreground/background separation unit 105, respectively.

[0282] For example, the separated image processing unit 106 generates coefficients which are used in the class classification adaptation processing for generating an even higher resolution image for each of the image in the background region, background component image in the uncovered background region, foreground component image in the uncovered background region, background component image in the covered background region, foreground component image in the covered background region, and image in the foreground region.

[0283] For example, the separated image processing unit 106 creates an even higher resolution image by applying the class classification adaptation processing for each of the image in the background region, background component image in the uncovered background region, foreground component image in the uncovered background region, background component image in the covered background region, foreground component image in the covered background region, and image in the foreground region.

[0284] Also, for example, the separated image processing unit 106 applies the processing for edge enhancement with differing degrees by using a different coefficient for each of the image in the background region, the background component image in the uncovered background region, the foreground component image in the uncovered background region, the background component image in the covered background region, the foreground component image in the covered background region, and the image in the foreground region.

[0285] The input images supplied to the image processing device will now be described, referring to FIG. 12 through FIG. 27.

[0286] FIG. 12 is a diagram which describes image-taking with a sensor. The sensor comprises a CCD video camera or the like, for example, including a CCD (Charge-Coupled Device) area sensor which is a solid-state image-taking device. An object 111 corresponding to the foreground in the real world moves between an object 112 corresponding to the background in the real world, and the sensor, for example, from the left side to the right side horizontally in the drawing.

[0287] The sensor takes images of the object 111 corresponding to the foreground with the object 112 corresponding to the background. The sensor outputs the taken images in increments of one frame. For example, the sensor outputs images of 30 frames per second. In this case, the exposure period of the sensor is 1/30 seconds. The exposure period represents a period from the sensor beginning conversion of input light into electric charges, up to the end of conversion of input light to electric charges. The exposure period will be also referred to as a shutter period hereafter.

[0288] FIG. 13 is a diagram which describes an arrangement of pixels. In FIG. 13, A through I denote individual pixels. These pixels are arranged on a plane corresponding to the image. One detecting element corresponding to one pixel is disposed on the sensor. Upon the sensor taking images, one detecting element outputs pixel values corresponding to one pixel which makes up the image. For example, a position in the X direction of the detecting elements corresponds to a position in the horizontal direction on the image, and a position in the Y direction of the detecting elements corresponds to a position in the vertical direction on the image.

[0289] As shown in FIG. 14, for example, the detecting element of the CCD converts the input light into charges for a period corresponding to the shutter period, and accumulates the converted charges. The quantity of charges is approximately proportional to the strength of the input light and the period during which the light is input. The detecting element adds the charges converted from the input light to the accumulated charges in the period corresponding to the shutter period. That is to say, the detecting element integrates the input light during the period corresponding to the shutter period, and accumulates the amount of charges corresponding to the integrated light. It can also be said that the detecting element has integrating effects with regard to time.

[0290] The charges accumulated in the detecting element are converted into a voltage value by a circuit not shown in the drawings, which is further converted to pixel values such as digital data or the like, and is output. Accordingly, individual pixel values output from a sensor have values projected in one-dimensional space, which is from a result wherein a given portion having a spatial extension of the object corresponding to the foreground or the background, is integrated for the shutter period.

[0291] The image processing device extracts valid information buried in output signals due to such accumulation operations of the sensor, such as the mixture ratio α, for example.

[0292] FIG. 15A and FIG. 15B are diagrams which describe the image which is obtained by taking image of the object corresponding to the moving foreground and the object corresponding to the still background. FIG. 15A illustrates the image which is obtained by taking image of the object corresponding to the foreground with movement and the object corresponding to the still background. With the example shown in FIG. 15A, the object corresponding to the foreground moves from the left to the right horizontally in the drawing.

[0293] FIG. 15B is a model diagram wherein pixel values corresponding to one line of the image shown in FIG. 15A develop over the time direction. The horizontal direction in FIG. 15B corresponds to the spatial direction X in FIG. 15A.

[0294] The pixel values of pixels in the background regions are made up of only the background components, i.e., the image components corresponding to the background objects. The pixel values of pixels in the foreground regions are made up of only the foreground components, i.e., the image components corresponding to the foreground objects.

[0295] The pixel values of pixels in mixed regions are made up of the background components and the foreground components. Since the pixel values in the mixed region consists of the background components and the foreground components, the mixed region can also be said to be a distortion region. The mixed regions are further classified into covered background regions and uncovered background regions.

[0296] The covered background region is a mixed region at a position corresponding to a leading portion in the progress direction of the foreground object with regard to the foreground region, and accordingly is a region wherein the background components are covered by the foreground corresponding to elapsing of time.

[0297] Conversely, the uncovered background region is a mixed region at a position corresponding to a trailing portion in the progress direction of the foreground object with regard to the foreground region, and accordingly is a region wherein the background components emerge corresponding to elapsing of time.

[0298] As described above, images including the foreground region, background region, covered background region, or uncovered background region, are input as input images to the region specifying unit 103, the mixture ratio calculating unit 104, and the foreground/background separation unit 105.

[0299] FIG. 16 is a diagram which describes the background region, foreground region, mixed region, covered background region, and uncovered background region, as described above. In the event of corresponding to the images shown in FIG. 15A, the background region is the still portion, the foreground region is the moving portion, the covered background region of the mixed region is the portion which changes from the background to the foreground, and the uncovered background region of the mixed region is the portion which changes from the foreground to the background.

[0300] FIG. 17 is a model diagram wherein pixel values of the pixels arrayed adjacently in one line in the image that has been taken of the objects corresponding to the still foregrounds and the objects corresponding to the still backgrounds, develop over the time direction. For example, pixels arrayed in one line in a screen may be selected, as pixels adjacently arrayed in one line.

[0301] The pixel values F01 through F04 shown in FIG. 17 are pixel values of pixels corresponding to the still foreground object. The pixel values B01 through B04 shown in FIG. 17 are pixel values of pixels corresponding to the still background object.

[0302] The vertical direction in FIG. 17 represents elapsing of time from the top to the bottom in the drawing. The position of the upper side of the rectangle in FIG. 17 corresponds to the time at which the sensor begins conversion of the input light into charges, and the position of the lower side of the rectangle in FIG. 17 corresponds to the time at which the sensor ends the conversion of the input light into charges. That is to say, the distance from the upper side to the lower side of the rectangle in FIG. 17 corresponds to the shutter period.

[0303] An arrangement wherein the shutter period equals the frame interval will now be described below, by way of an example.

[0304] The horizontal direction in FIG. 17 corresponds to the spatial direction X as described in FIG. 15A. More particularly, shown by way of an example in FIG. 17, the distance from the left side of the rectangle denoted by “F01” to the right side of the rectangle denoted by “B04” in FIG. 17, is eight times long as the pixel pitch, that is to say, corresponds to the interval of eight continuous pixels.

[0305] In the event that the foreground objects and the background objects keep still, the light input to the sensor is not altered during the period corresponding to the shutter period.

[0306] Now, the period corresponding to the shutter period is divided into two or more periods of equal length. For example, in the event that the virtual dividing number is 4, the model diagram shown in FIG. 17 can be represented by the model shown in FIG. 18. The virtual dividing number is set corresponding to the movement amount v or the like of the object corresponding to the foreground within the shutter period. For example, corresponding to the movement amount v of 4, the virtual dividing number is 4, and the period corresponding to the shutter period is divided into 4 periods.

[0307] The uppermost row in the drawing corresponds to the first of the divided periods from the shutter being opened. The second row from the top in the drawing corresponds to the second of the divided periods from the shutter being opened. The third row from the top in the drawing corresponds to the third of the divided periods from the shutter being opened. The fourth row from the top in the drawing corresponds to the fourth of the divided periods from the shutter being opened.

[0308] The divided shutter period corresponding to the movement amount v is also referred to as a shutter period/v hereafter.

[0309] In the event that the object corresponding to the foreground keeps still, the foreground component F01/v equals the value in which the pixel value F01 is divided by the virtual dividing number, since the light input to the sensor is not altered. Similarly, in the event that the object corresponding to the foreground keeps still, the foreground component F02/v equals the value of the pixel value F02 being divided by the virtual dividing number, the foreground component F03/v equals the value of the pixel value F03 being divided by the virtual dividing number, and the foreground component F04/v equals the value of the pixel value F04 being divided by the virtual dividing number.

[0310] In the event that the object corresponding to the background keeps still, the background component B01/v equals the value of the pixel value B01 being divided by the virtual dividing number, since the light input to the sensor is not altered. Similarly, in the event that the object corresponding to the background keeps still, the background component B02/v equals the value of the pixel value B02 being divided by the virtual dividing number, B03/v equals the value of the pixel value B03 being divided by the virtual dividing number, and B04/v equals the value of the pixel value B04 being divided by the virtual dividing number.

[0311] That is to say, in the event that the object corresponding to the foreground keeps still, the foreground component F01/v corresponding to the first shutter period/v from the shutter opening, the foreground component F01/v corresponding to the second shutter period/v from the shutter opening, the foreground component F01/v corresponding to the third shutter period/v from the shutter opening, and the foreground component F01/v corresponding to the fourth shutter period/v from the shutter opening, are the same value, since the light corresponding to the foreground object which is input to the sensor is not altered during the period corresponding to the shutter period. F02/v through F04/v have the same relationship as F01/v.

[0312] In the event that the object corresponding to the background keeps still, the background component B01/v corresponding to the first shutter period/v from the shutter opening, the background components B01/v corresponding to the second shutter period/v from the shutter opening, the background components B01/v corresponding to the third shutter period/v from the shutter opening, and the background components B01/v corresponding to the fourth shutter period/v from the shutter opening, are the same value, since the light corresponding to the background object which is input to the sensor is not altered during the period corresponding to the shutter period. B02/v through B04/v have the same relationship.

[0313] A case will now be described wherein the object corresponding to the foreground moves while the object corresponding to the background keeps still.

[0314] FIG. 19 is a model diagram wherein pixel values of the pixels on one line including the covered background region develop over the time direction in the event that the object corresponding to the foreground moves towards the right side in the drawing. In FIG. 19, the movement amount v of the foreground is 4. Since one frame is a short period, an assumption may be made that the object corresponding to the foreground is a rigid body, and moves at a constant velocity.

[0315] In FIG. 19, the object image corresponding to the foreground moves so as to be displayed at a position four pixels to the right in the following frame, with a given frame as a reference.

[0316] In FIG. 19, the left-most pixel through the fourth pixel from the left, belong to the foreground region. In FIG. 19, the fifth through the seventh pixels from the left belong to the covered background region of the mixed region. In FIG. 19, the right-most pixel belongs to the background region.

[0317] Since the object corresponding to the foreground moves so as to hide the object corresponding to the background with elapsing of time, the components contained in the pixel values of the pixels which belong to the covered background region change from the background components to the foreground components at a certain point of the period corresponding to the shutter period.

[0318] For example, the pixel value M shown with a heavy frame in FIG. 19, is represented by Expression (1).
M=B02/v+B02/v+F07/v+F06/v  (1)

[0319] For example, since the fifth pixel from the left includes a background component corresponding to one shutter period/v and foreground components corresponding to the three shutter period/vs, the mixture ratio α of the fifth pixel from the left is ¼. Since the sixth pixel from the left contains background components corresponding to the two shutter period/vs and foreground components corresponding to the two shutter period/vs, the mixture ratio α of the sixth pixel from the left is ½. Since the seventh pixel from the left includes background components corresponding to the three shutter period/vs and a foreground component corresponding to the one shutter period/v, the mixture ratio α of the seventh pixel from the left is ¾.

[0320] Since an assumption may be made that the object corresponding to the foreground is a rigid body and the foreground image moves at a constant velocity so as to be displayed at a position four pixels to the right in the following frame, the foreground component F07/v of the first shutter period/v from the shutter opening of the fourth pixel from the left in FIG. 19, for example, equals the foreground component corresponding to the second shutter period/v from the shutter opening of the fifth pixel from the left in FIG. 19. Similarly, the foreground component F07/v equals the foreground component corresponding to the third shutter period/v from the shutter opening of the sixth pixel from the left in FIG. 19, and the foreground component corresponding to the fourth shutter period/v from the shutter opening of the seventh pixel from the left in FIG. 19, respectively.

[0321] Since an assumption may be made that the object corresponding to the foreground is a rigid body and that the foreground image moves at a constant velocity so as to be displayed at a point four pixels to the right in the following frame, the foreground component F06/v of the first shutter period/v from the shutter opening of the third pixel from the left in FIG. 19, for example, equals the foreground component corresponding to the second shutter period/v from the shutter opening of the fourth pixel from the left in FIG. 19. Similarly, the foreground component F06/v equals the foreground component corresponding to the third shutter period/v from the shutter opening of the fifth pixel from the left in FIG. 19, and the foreground component corresponding to the fourth shutter period/v from the shutter opening of the sixth pixel from the left in FIG. 19, respectively.

[0322] Since an assumption may be made that the object corresponding to the foreground is a rigid body and the foreground image moves at a constant velocity so as to be displayed at a position four pixels to the right in the following frame, the foreground component F05/v of the first shutter period/v from the shutter opening of the second pixel from the left in FIG. 19, for example, equals the foreground component corresponding to the second shutter period/v from the shutter opening of the third pixel from the left in FIG. 19. Similarly, the foreground component F05/v equals the foreground component corresponding to the third shutter period/v from the shutter opening of the fourth pixel from the left in FIG. 19, and the foreground component corresponding to the fourth shutter period/v from the shutter opening of the fifth pixel from the left in FIG. 19, respectively.

[0323] Since an assumption may be made that the object corresponding to the foreground is a rigid body and the foreground image moves at a constant velocity so as to be displayed at a position four pixels to the right in the following frame, the foreground component F04/v of the first shutter period/v from the shutter opening of the left-most pixel in FIG. 19, for example, equals the foreground component corresponding to the second shutter period/v from the shutter opening of the second pixel from the left in FIG. 19. Similarly, the foreground component F04/v equals the foreground component corresponding to the third shutter period/v from the shutter opening of the third pixel from the left in FIG. 19, and the foreground component corresponding to the fourth shutter period/v from the shutter opening of the fourth pixel from the left in FIG. 19, respectively.

[0324] As described above, the foreground region corresponding to the moving object includes movement blurring, so this can be said to be a distorted region.

[0325] FIG. 20 is a model diagram wherein the pixel values of the pixels on one line including the uncovered background region develop over the time direction in the event that the foreground moves toward the right side in the drawing. In FIG. 20, the movement amount v of the foreground is 4. Since one frame is a short time, an assumption may be made that the object corresponding to the foreground is a rigid body, and moves at a constant velocity. In FIG. 20, the object image corresponding to the foreground moves to the right side by four pixels in the following frame with a given frame as a reference.

[0326] In FIG. 20, the left-most pixel through the fourth pixel from the left, belong to the background region. In FIG. 20, the fifth through the seventh pixels from the left belong to the mixed region of the uncovered background. In FIG. 20, the right-most pixel belongs to the foreground region.

[0327] Since the object corresponding to the foreground which has hidden the object corresponding to the background moves so as to be removed from the front of the object corresponding to the background with elapsing of time, the components included in the pixel values of the pixels which belong to the uncovered background region change from the foreground components to the background components at a certain point in the period corresponding to the shutter period.

[0328] For example, the pixel value M′ indicated with a heavy frame in FIG. 20, is represented by Expression (2).
M′=F02/v+F01/v+B26/v+B26/v  (2)

[0329] For example, since the fifth pixel from the left includes the background components corresponding to the three shutter period/vs, and the foreground component corresponding to the one shutter period/v, the mixture ratio α of the fifth pixel from the left is ¾. Since the sixth pixel from the left includes the background components corresponding to the two shutter period/vs and the foreground components corresponding to the two shutter period/vs, the mixture ratio α of the sixth pixel from the left is ½. Since the seventh pixel from the left includes the background component corresponding to the one shutter period/v and the foreground components corresponding to the three shutter period/vs, the mixture ratio α of the seventh pixel from the left is ¼.

[0330] Further generalizing Expression (1) and Expression (2), the pixel value M is represented by Expression (3).

[0331] $\begin{array}{cc}M=\alpha ·B+\sum _i{F}_i/v& \left(3\right)\end{array}$

[0332] Here, α denotes the mixture ratio. B denotes the pixel value of the background, and Fi/v denotes the foreground component.

[0333] Since an assumption may be made that the object corresponding to the foreground is a rigid body and moves at a constant velocity, and the movement amount v is 4, for example, the foreground component F01/v of the first shutter period/v from the shutter opening of the fifth pixel from the left in FIG. 20 equals the foreground component corresponding to the second shutter period/v from the shutter opening of the sixth pixel from the left in FIG. 20. Similarly, F01/v equals the foreground component corresponding to the third shutter period/v from the shutter opening of the seventh pixel from the left in FIG. 20, and the foreground component corresponding to the fourth shutter period/v from the shutter opening of the eighth pixel from the left in FIG. 20, respectively.

[0334] Since an assumption may be made that the object corresponding to the foreground is a rigid body and moves at a constant velocity, and the virtual dividing number is 4, the foreground component F02/v of the first shutter period/v from the shutter opening of the sixth pixel from the left in FIG. 20, for example, equals the foreground component corresponding to the second shutter period/v from the shutter opening of the seventh pixel from the left in FIG. 20. Similarly, the foreground component F02/v equals the foreground component corresponding to the third shutter period/v from the shutter opening of the eighth pixel from the left in FIG. 20.

[0335] Since an assumption may be made that the object corresponding to the foreground is an rigid body and moves at a constant velocity, and movement amount v is 4, the foreground component F03/v of the first shutter period/v from the shutter opening of the seventh pixel from the left in FIG. 20, for example, equals the foreground component corresponding to the second shutter period/v from the shutter opening of the eighth pixel from the left in FIG. 20.

[0336] While a description has been made in the description of FIG. 18 through FIG. 20 wherein the virtual dividing number is 4, the virtual dividing number corresponds to the movement amount v. The movement amount v generally corresponds to the movement velocity of the object corresponding to the foreground. For example, in the event that the object corresponding to the foreground moves so as to be displayed at a position-four pixels to the right in the following frame with a given frame as a reference, the movement amount v is 4. The virtual dividing number is 4 corresponding to the movement amount v. Similarly, for example, in the event that the object corresponding to the foreground moves so as to be displayed at a position six pixels to the left in the following frame with a given frame as a reference, the movement amount v is 6, and the virtual dividing number is 6.

[0337] FIG. 21 and FIG. 22 illustrate the relationship between the foreground region, the background region, and the mixed region which consists of the covered background region or the uncovered background region, and the foreground components and the background components, corresponding to the divided shutter period.

[0338] FIG. 21 illustrates an example wherein the pixels of the foreground region, the background region, and the mixed region, are extracted from the image including the foreground corresponding to the object which moves in front of the still background. The reference character A shown in FIG. 21 denotes an object which moves in front of the still background. In the example shown in FIG. 21, the object corresponding to the foreground denoted by the reference character A moves horizontally with regard to the screen.

[0339] The frame #n+1 is the frame following the frame #n, and the frame #n+2 is the frame following the frame #n+1.

[0340] FIG. 22 illustrates a model wherein the pixels of the foreground region, the background region, and the mixed region are extracted from one of frame #n through frame #n+2, and the pixel values of the extracted pixels are developed over the time direction, with the movement amount v at 4.

[0341] Since the object corresponding to the foreground moves, the pixel values of the foreground region consist of four different foreground components corresponding to the period of shutter period/v. For example, the left-most pixel of the pixels of the foreground region shown in FIG. 22 consists of F01/v, F02/v, F03/v, and F04/v. That is to say, the pixels of the foreground region include movement blurring.

[0342] Since the object corresponding to the background keeps still, the light corresponding to the background input to the sensor is not altered during the period corresponding to the shutter period. In this case, the pixel values of the background region do not contain movement blurring.

[0343] The pixel value of the pixel which belongs to the mixed region made up of the covered background region or the uncovered background region consists of the foreground components and the background components.

[0344] Next, a model will be described wherein, in the event that the image corresponding to the object moves, the pixel values of the pixels which are arrayed adjacently in a single line on multiple frames, and at the same position in the frames, develop over the time direction. For example, in the event that the image corresponding to the object moves horizontally on the screen, the pixels arrayed in a single line can be selected as pixels arrayed adjacently in a single line.

[0345] FIG. 23 is a model diagram wherein the pixel values of pixels arrayed adjacently in a single line on three frames of images which are taken of the object corresponding to the still background, and are at the same position in the frames, develop over the time direction. The frame #n is the frame following the frame #n−1, and the frame #n+1 is the frame following the frame #n. Other frames are denoted in the same way.

[0346] The pixel values of the B01 through B12 shown in FIG. 23 are the pixel values of the pixels corresponding to the object of the still background. Since the object corresponding to the background keeps still, the pixel values of the corresponding pixels do not change in the frame #n−1 through the frame #n+1. For example, the pixels in the frame #n and the pixels in the frame #n+1 at the position corresponding to the pixel having a pixel value B05 in the frame #n−1, have a pixel value B05, respectively.

[0347] FIG. 24 is a model diagram wherein the pixel values of pixels arrayed adjacently in a single line on three frames of images taken of the object corresponding to the foreground which moves to the right side in the drawing with the object corresponding to the still background, and at the same position in the frames, develop over the time direction. The models shown in FIG. 24 includes the covered background region.

[0348] Since an assumption may be made in FIG. 24 that the object corresponding to the foreground is a rigid body and moves at a constant velocity, and the foreground image moves so as to be displayed at a position four pixels to the right side in the following frame, the foreground movement amount v is 4, and the virtual dividing number is 4.

[0349] For example, the foreground component of the first shutter period/v from the shutter opening of the left-most pixel of the frame #n−1 in FIG. 24 is F12/v, the foreground component of the second shutter period/v from the shutter opening of the second pixel from the left in FIG. 24 is also F12/v. The foreground component of the third shutter period/v from the shutter opening of the third pixel from the left in FIG. 24, and the foreground component of the fourth shutter period/v from the shutter opening of the fourth pixel from the left in FIG. 24, are F12/v.

[0350] The foreground component of the second shutter period/v from the shutter opening of the left-most pixel in the frame #n−1 in FIG. 24 is F11/v, and the foreground component of the third shutter period/v from the shutter opening of the second pixel from the left in FIG. 24 is also F11/v. The foreground component of the fourth shutter period/v from the shutter opening of the third pixel from the left in FIG. 24 is F11/v.

[0351] The foreground component of the third shutter period/v from the shutter opening of the left-most pixel in the frame #n−1 in FIG. 24 is F10/v, and the foreground component of the fourth shutter period/v from the shutter opening of the second pixel from the left in FIG. 24 is also F10/v. The foreground component of the fourth shutter period/v from the shutter opening of the left-most pixel in the frame #n−1 in FIG. 24 is F09/v.

[0352] Since the object corresponding to the background keeps still, the background component of the first shutter period/v from the shutter opening of the second pixel from the left in the frame #n−1 in FIG. 24 is B01/v. The background components of the first and second shutter period/vs from the shutter opening of the third pixel from the left in the frame #n−1 in FIG. 24 are B02/v. The background components of the first through third shutter period/vs from the shutter opening of the fourth pixel from the left in the frame #n−1 in FIG. 24 are B03/v.

[0353] In the frame #n−1 in FIG. 24, the left-most pixel belongs to the foreground region, and the second through fourth pixels from the left belong to the mixed region of the covered background region.

[0354] The fifth through twelfth pixels from the left in the frame #n−1 in FIG. 24 belong to the background region, and the pixel values thereof are B04 through B11, respectively.

[0355] The first through fifth pixels from the left in the frame #n in FIG. 24 belong to the foreground region. The foreground component of the shutter period/v in the foreground region in the frame #n, is one of F05/v through F12/v.

[0356] Since an assumption may be made that the object corresponding to the foreground is a rigid body and moves at a constant velocity, and the foreground image moves so as to be displayed at a position four pixels to the right side in the following frame, the foreground component of the first shutter period/v from the shutter opening of the fifth pixel from the left in the frame #n in FIG. 24 is F12/v, the foreground component of the second shutter period/v from the shutter opening of the sixth pixel from the left in FIG. 24 is also F12/v. The foreground component of the third shutter period/v from the shutter opening of the seventh pixel from the left in FIG. 24, and the foreground component of the fourth shutter period/v from the shutter opening of the eighth pixel from the left in FIG. 24, are F12/v.

[0357] The foreground component of the second shutter period/v from the shutter opening of the fifth pixel from the left in the frame #n in FIG. 24 is F11/v, and the foreground component of the third shutter period/v from the shutter opening of the sixth pixel from the left in FIG. 24 is also F11/v. The foreground component of the fourth shutter period/v from the shutter opening of the seventh pixel from the left in FIG. 24 is F11/v.

[0358] The foreground component of the third shutter period/v from the shutter opening of the fifth pixel from the left in the frame #n in FIG. 24 is F10/v, and the foreground component of the fourth shutter period/v from the shutter opening of the sixth pixel from the left in FIG. 24 is also F10/v. The foreground component of the fourth shutter period/v from the shutter opening of the fifth pixel from the left in the frame #n in FIG. 24 is F09/v.

[0359] Since the object corresponding to the background keeps still, the background component of the first shutter period/v from the shutter opening of the sixth pixel from the left in the frame #n in FIG. 24 is B05/v. The background components of the first and second shutter period/vs from the shutter opening of the seventh pixel from the left in the frame #n in FIG. 24 are B06/v. The background components of the first through third shutter period/vs from the shutter opening of the eighth pixel from the left in the frame #n in FIG. 24 are B07/v.

[0360] In the frame #n in FIG. 24, the sixth through eighth pixels from the left belong to the mixed region of the covered background region.

[0361] The ninth through twelfth pixels from the left in the frame #n in FIG. 24 belong to the background region, and the pixel values are B08 through B11, respectively.

[0362] The first through ninth pixels from the left in the frame #n+1 in FIG. 24 belong to the foreground region. The foreground component of the shutter period/v in the foreground region in the frame #n+1 is one of F01/v through F12/v.

[0363] Since an assumption may be made that the object corresponding to the foreground is a rigid body and moves at a constant velocity, and the foreground image moves so as to be displayed at a position four pixels to the right side in the following frame, the foreground component of the first shutter period/v from the shutter opening of the ninth pixel from the left in the frame #n+1 in FIG. 24 is F12/v, and the foreground component of the second shutter period/v from the shutter opening of the tenth pixel from the left in FIG. 24 is also F12/v. The foreground component of the third shutter period/v from the shutter opening of the eleventh pixel from the left in FIG. 24, and the foreground component of the fourth shutter period/v from the shutter opening of the twelfth pixel from the left in FIG. 24, are F12/v.

[0364] The foreground component of the second shutter period/v from the shutter opening of the ninth pixel from the left in the frame #n+1 in FIG. 24 is F11/v, and the foreground component of the third shutter period/v from the shutter opening of the tenth pixel from the left in FIG. 24 is also F11/v. The foreground component of the fourth shutter period/v from the shutter opening of the eleventh pixel from the left in FIG. 24 is F11/v.

[0365] The foreground component of the third shutter period/v from the shutter opening of the ninth pixel from the left in the frame #n+1 in FIG. 24 is F10/v, and the foreground component of the fourth shutter period/v from the shutter opening of the tenth pixel from the left in FIG. 24 is also F10/v. The foreground component of the fourth shutter period/v from the shutter opening of the ninth pixel from the left in the frame #n+1 in FIG. 24 is F09/v.

[0366] Since the object corresponding to the background keeps still, the background component of the first shutter period/v from the shutter opening of the tenth pixel from the left in the frame #n+1 in FIG. 24 is B09/v. The background components of the first and second shutter period/vs from the shutter opening of the eleventh pixel from the left in the frame #n+1 in FIG. 24 are B10/v. The background components of the first through third shutter period/vs from the shutter opening of the twelfth pixel from the left in the frame #n+1 in FIG. 24 are B11/v.

[0367] In the frame #n+1 in FIG. 24, the tenth through twelfth pixels from the left side correspond to the mixed region which is the covered background region.

[0368] FIG. 25 is a model diagram wherein the foreground components are extracted from the pixel values illustrated in FIG. 24.

[0369] FIG. 26 is a model diagram wherein the pixel values of the pixels adjacently arrayed in a row in three frames of the images which are taken of the foreground corresponding to the object which moves to the right side in the drawing with the still background, and are at the same position in the frames, develop over the time direction. In FIG. 26, the model diagram includes the uncovered background region.

[0370] In FIG. 26, an assumption may be made that the object corresponding to the foreground is a rigid body, and moves at a constant velocity. Since the object corresponding to the foreground moves so as to be displayed at a position four pixels to the right side in the following frame, the movement amount v is 4.

[0371] For example, the foreground component of the first shutter period/v from the shutter opening of the left-most pixel in the frame #n−1 in FIG. 26 is F13/v, and the foreground component of the second shutter period/v from the shutter opening of the second pixel from the left in FIG. 26 is also F13/v. The foreground component of the third shutter period/v from the shutter opening of the third pixel from the left in FIG. 26, and the foreground component of the fourth shutter period/v from the shutter opening of the fourth pixel from the left in FIG. 26, are F13/v.

[0372] The foreground component of the first shutter period/v from the shutter opening of the second pixel from the left in the frame #n−1 in FIG. 26 is F14/v, and the foreground component of the second shutter period/v from the shutter opening of the third pixel from the left in FIG. 26 is also F14/v. The foreground component of the first shutter period/v from the shutter opening of the third pixel from the left in FIG. 26 is F15/v.

[0373] Since the object corresponding to the background keeps still, the background component of the second through fourth shutter period/vs from the shutter opening of the left-most pixel in the frame #n−1 in FIG. 26 is B25/v. The background components of the third and fourth shutter period/vs from the shutter opening of the second pixel from the left in the frame #n−1 in FIG. 26 are B26/v. The background component of the fourth shutter period/v from the shutter opening of the third pixel from the left in the frame #n−1 in FIG. 26 is B27/v.

[0374] In the frame #n−1 in FIG. 26, the left-most pixel through the third pixel belong to a mixed region of the uncovered background region.

[0375] The fourth through twelfth pixels from the left in the frame #n−1 in FIG. 26 belong to the foreground region. The foreground component in the frame is one of F13/v through F24/v.

[0376] The left-most pixel through the fourth pixel from the left in the frame #n in FIG. 26 belong to the background region, and the pixel values are B25 through B28, respectively.

[0377] Since an assumption may be made that the object corresponding to the foreground is a rigid body and moves at a constant velocity, and the foreground image moves so as to be displayed at a position four pixels to the right side in the following frame, the foreground component of the first shutter period/v from the shutter opening of the fifth pixel from the left in the frame #n in FIG. 26 is F13/v, and the foreground component of the second shutter period/v from the shutter opening of the sixth pixel from the left in FIG. 26 is also F13/v. The foreground component of the third shutter period/v from the shutter opening of the seventh pixel from the left in FIG. 26, and the foreground component of the fourth shutter period/v from the shutter opening of the eighth pixel from the left in FIG. 26, are F13/v.

[0378] The foreground component of the first shutter period/v from the shutter opening of the sixth pixel from the left in the frame #n in FIG. 26 is F14/v, and the foreground component of the second shutter period/v from the shutter opening of the seventh pixel from the left in FIG. 26 is also F14/v. The foreground component of the first shutter period/v from the shutter opening of the eighth pixel from the left in FIG. 26 is F15/v.

[0379] Since the object corresponding to the background keeps still, the background components of the second through fourth shutter period/vs from the shutter opening of the fifth pixel from the left in the frame #n in FIG. 26 are B29/v. The background components of the third and fourth shutter period/vs from the shutter opening of the sixth pixel from the left in the frame #n in FIG. 26 are B30/v. The background component of the fourth shutter period/v from the shutter opening of the seventh pixel from the left in the frame #n in FIG. 26 is B31/v.

[0380] In the frame #n in FIG. 26, the fifth through seventh pixels from the left belong to the mixed region of the uncovered background region.

[0381] The eighth through twelfth pixels from the left in the frame #n in FIG. 26 belong to the foreground region. The value corresponding to the period of the shutter period/v in the foreground region in the frame #n is one of F13/v through F20/v.

[0382] The left-most pixel through the eighth pixel from the left in the frame #n+1 in FIG. 26, belong to the background region, and the pixel values thereof are B25 through B32, respectively.

[0383] Since an assumption may be made that the object corresponding to the foreground is a rigid body and moves at a constant velocity, and the foreground image moves so as to be displayed at a position four pixels to the right side in the following frame, the foreground component of the first shutter period/v from the shutter opening of the ninth pixel from the left in the frame #n+1 in FIG. 26 is F13/v, and the foreground component of the second shutter period/v from the shutter opening of the tenth pixel from the left in FIG. 26 is also F13/v. The foreground component of the third shutter period/v from the shutter opening of the eleventh pixel from the left in FIG. 26, and the foreground component of the fourth shutter period/v from the shutter opening of the twelfth pixel from the left in FIG. 26, are F13/v.

[0384] The foreground component of the first shutter period/v from the shutter opening of the tenth pixel from the left in the frame #n+1 in FIG. 26 is F14/v, and the foreground component of the second shutter period/v from the shutter opening of the eleventh pixel from the left in FIG. 26 is also F14/v. The foreground component of the first shutter period/v from the shutter opening of the twelfth pixel from the left in FIG. 26 is F15/v.

[0385] Since the object corresponding to the background keeps still, the background components of the second through fourth shutter period/vs from the shutter opening of the ninth pixel from the left in the frame #n+1 in FIG. 26 are B33/v. The background components of the third and fourth shutter period/vs from the shutter opening of the tenth pixel from the left in the frame #n+1 in FIG. 26 are B34/v. The background component of the fourth shutter period/v from the shutter opening of the eleventh pixel from the left in the frame #n+1 in FIG. 26 is B35/v.

[0386] In the frame #n+1 in FIG. 26, the ninth through eleventh pixels from the left belong to the mixed region of the uncovered background region.

[0387] The twelfth pixel from the left in the frame #n+1 in FIG. 26 belongs to the foreground region. The foreground component of the shutter period/v in the foreground region in the frame #n+1 is one of F13/v through F16/v.

[0388] FIG. 27 is a model diagram of the image wherein the foreground components are extracted from the pixel values shown in FIG. 26.

[0389] FIG. 28 is a diagram which illustrates how the input image divided into the image in the foreground region, the image in the background region, the foreground component image in the covered background region, the background component image in the covered background region, the foreground component image in the uncovered background region, and the background component image in the uncovered background region, correspond to a model diagram wherein the pixel values of pixels develop over the time direction.

[0390] As shown in FIG. 28, the input image is classified into the foreground region, background region, covered background region, and uncovered background region, by the region specifying unit 103. The input image is separated into the image in the foreground region, the image in the background region, the foreground component image in the covered background region, the background component image in the covered background region, the foreground component image in the uncovered background region, the background component image in the uncovered background region, by the foreground/background separation unit 105 based upon the specified regions, i.e., the foreground region, background region, covered background region, and uncovered background region, and the mixture ratio α detected by the mixture ratio calculation unit 104.

[0391] The separated images, i.e., the image in the foreground region, the image in the background region, the foreground component image in the covered background region, the background component image in the covered background region, the foreground component image in the uncovered background region, the background component image in the uncovered background region, are processed, respectively.

[0392] FIG. 29 is a diagram which illustrates an example of the image divided into the foreground region, the background region, and the mixed region. The region specifying unit 103 specifies the foreground region, background region, and mixed region, of the input image. The image processing device can divide the input image into the image of the foreground region, image of the background region, and image of the mixed region, based upon the region information indicating the foreground region, background region, and mixed region.

[0393] As shown in FIG. 30, the foreground/background separation unit 105 separates the image of the mixed region into the foreground component image and the background component image based upon the region information supplied from the region specifying unit 103 and the mixture ratio α supplied from the mixture ratio calculating unit 104.

[0394] FIG. 31 illustrates the flowchart which describes the processing for an image with the image processing device according to the present invention.

[0395] In Step S101, the region specifying unit 103 specifies the foreground region, background region, covered background region, and uncovered background region of the input image, based upon the movement vector and the position information thereof supplied from the movement detecting unit 102 and the input image. Details of the processing for region specifying will be described later.

[0396] In Step S102, the mixture ratio calculating unit 104 calculates the mixture ratio α based upon the region information supplied from the region specifying unit 103 and the input image. Details of the processing of the mixture ratio calculating unit 104 calculating the mixture ratio α will be described later.

[0397] In Step S103, the foreground/background separation unit 105 separates the input image into the image in the foreground region, the image in the background region, the foreground component image in the covered background region, the background component image in the covered background region, the foreground component image in the uncovered background, and the background component image in the uncovered background region, based upon the region information supplied from the region specifying unit 103 and the mixture ratio α supplied from the mixture ratio calculation unit 104. Details of the processing for separation of an image by the foreground/background separation unit 105 will be described later.

[0398] In Step S104, the separated image processing unit 106 performs image processing for each of the separated images, i.e., the image in the foreground region, the image in the background region, the foreground component image in the covered background region, the background component image in the covered background region, the foreground component image in the uncovered background region, and the background component image in the uncovered background region, and the processing ends. Details of the image processing performed by the separated image processing unit 106 will be described later.

[0399] As described above, the image processing device according to the present invention separates the input image into the image in the foreground region, the image in the background region, the foreground component image in the covered background region, the background component image in the covered background region, the foreground component image in the uncovered background region, and the background component image in the uncovered background region, and performs the image processing for each of the separated images, i.e., the image in the foreground region, the image in the background region, the foreground component image in the covered background region, the background component image in the covered background region, the foreground component image in the uncovered background region, and the background component image in the uncovered background region, which are separated.

[0400] FIG. 32 is a block diagram which illustrates an example of the configuration of the region specifying unit 103. The region specifying unit 103, of which configuration is shown in FIG. 32, does not use the movement vectors. Frame memory 201 stores the input images in increments of one frame. In the event that the object of the processing is the frame #n, the frame memory 201 stores the frame #n−2 which is two frames previous from the frame #n, the frame #n−1 which is one frame previous from the frame #n, the frame #n, the frame #n+1 which is one frame following the frame #n, and the frame #n+2 which is two frames following the frame #n.

[0401] A still/motion judgment unit 202-1 reads out the pixel value of the pixel in the frame #n+2, which is at the same position as the position of the pixel on the image, which is the object of specifying the region in the frame #n, and the pixel value of the pixel in the frame #n+1, which is at the same position as the position of the pixel on the image, which is the object of specifying the region of the frame #n, from the frame memory 201, and calculates the absolute value of the difference between the read out pixel values. The still/motion judgment unit 202-1 judges whether or not the absolute value of the difference between the pixel value in the frame #n+2 and the pixel value in the frame #n+1 is greater than the predetermined threshold value Th, and in the event that judgment is made that the absolute value of the difference is greater than the threshold value Th, the still/motion judgment unit 202-1 supplies the still/motion judgment, indicating motion, to a region judgment unit 203-1. In the event that judgment is made that the absolute value of the difference between the pixel value of the pixel in the frame #n+2 and the pixel value of the pixel in the frame #n+1 is equal to or less than the threshold value Th, the still/motion judgment unit 202-1 supplies the still/motion judgment, indicating “still”, to the region judgment unit 203-1.

[0402] A still/motion judgment unit 202-2 reads out the pixel value of the pixel in the frame #n+1, which is at the same position as the position of the pixel on the image, which is the object of specifying the region in the frame #n, and the pixel value of pixel which is the object in the frame #n from the frame memory 201, and calculates the absolute value of the difference between the pixel values. The still/motion judgment unit 202-2 judges whether or not the absolute value of the difference between the pixel value in the frame #n+1 and the pixel value in the frame #n is greater than the predetermined threshold value Th, and in the event that judgment is made that the absolute value of the difference between the pixel values is greater than the threshold value Th, the still/motion judgment indicating motion is supplied to the region judgment unit 203-1 and the region judgment unit 203-2. In the event that judgment is made that the absolute value of the difference between the pixel value of the pixel in the frame #n+1 and the pixel value of the pixel in the frame #n is equal to or smaller than the threshold value Th, the still/motion judgment unit 202-2 supplies the still/motion judgment, indicating “still”, to the region judgment unit 203-1 and the region judgment unit 203-2.

[0403] The still/motion judgment unit 202-3 reads out the pixel value of the pixel, which is the object of specifying the region in the frame #n, and the pixel value of the pixel in the frame #n−1, which is at the same position as the position on the image of the pixel, which is the object of specifying the region in the frame #n, from the frame memory 201, and calculates the absolute value of the difference between the pixel values. The still/motion judgment unit 202-3 judges whether or not the absolute value of the difference between the pixel value in the frame #n and the pixel value in the frame #n−1 is greater than the predetermined value Th, and in the event that judgment is made that the absolute value of the difference between the pixel values is greater than the threshold value Th, the still/motion judgment indicating motion is supplied to the region judgment unit 203-2 and the region judgment unit 203-3. In the event that judgment is made that the absolute value of the difference between the pixel value of the pixel in the frame #n and the pixel value of the pixel in the frame #n−1 is equal to or smaller than the threshold value Th, the still/motion judgment unit 202-3 supplies the still/motion judgment indicating “still” to the region judgment unit 203-2 and the region judgment unit 203-3.

[0404] The still/motion judgment unit 202-4 reads out the pixel value of the pixel in the frame #n−1 at the same position as the position of the pixel on the image, which is the object of specifying the region in the frame #n, and the pixel value of the pixel in the frame #n−2 at the same position as the position of the pixel on the image, which is the object of specifying the region in the frame #n, from the frame memory 201, and calculates the absolute value of the difference between the pixel values. The still/motion judgment unit 202-4 judges whether or not the absolute value of the difference between the pixel value in the frame #n−1 and the pixel value in the frame #n−2 is greater than the predetermined threshold value Th, and in the event that judgment is made that the absolute value of the difference between the pixel values is greater than the threshold value Th, the still/motion judgment indicating motion is supplied to the region judgment unit 203-3. In the event that judgment is made that the absolute value of the difference between the pixel value of the pixel in the frame #n−1 and the pixel value of the pixel in the frame #n−2 is equal to or smaller than the threshold value Th, the still/motion judgment unit 202-4 supplies the still/motion judgment indicating “still” to the region judgment unit 203-3.

[0405] In the event that the still/motion judgment supplied from the still/motion judgment unit 202-1 indicates “still”, and the still/motion judgment supplied from the still/motion judgment unit 202-2 indicates motion, the region judgment unit 203-1 judges that the pixel which is the object of specifying the region in the frame #n belongs to the uncovered background region, and sets the uncovered background region judgment flag corresponding to the judged pixel in the region, to “1”, which indicates that the pixel belongs to the uncovered background region.

[0406] In the event that the still/motion judgment supplied from the still/motion judgment unit 202-1 indicates motion, or the still/motion judgment supplied from the still/motion judgment unit 202-2 indicates still, the region judgment unit 203-1 judges that the pixel which is the object of specifying the region in the frame #n does not belong to the uncovered background region, and sets the uncovered background region judgment flag corresponding to the judged pixel in the region to “0”, which indicates that the pixel does not belong to the uncovered background region.

[0407] The region judgment unit 203-1 supplies the uncovered background region judgment flag which has been set to “1” or “0”, as described above, to the judgment flag storing memory 204.

[0408] In the event that the still/motion judgment supplied from the still/motion judgment unit 202-2 indicates “still”, and the still/motion judgment supplied from the still/motion judgment unit 202-3 indicates “still”, the region judgment unit 203-2 judges that the pixel which is the object of specifying the region in the frame #n belongs to the still region, and sets the still region judgment flag corresponding to the pixel judged in the region, to “1”, which indicates that the pixel belongs to the still region.

[0409] In the event that the still/motion judgment supplied from the still/motion judgment unit 202-2 indicates motion, or the still/motion judgment supplied from the still/motion judgment unit 202-3 indicates motion, the region judgment unit 203-2 judges that the pixel which is the object of specifying the region in the frame #n does not belong to the still region, and sets the still region judgment flag corresponding to the judged pixel in the region, to “0”, which indicates that the pixel does not belong to the still region.

[0410] The region judgment unit 203-2 supplies the still region judgment flag which has been set to “1” or “0” as described above, to judgment flag storing frame memory 204.

[0411] In the event that the still/motion judgment supplied from the still/motion judgment unit 202-2 indicates motion, and the still/motion judgment supplied from the still/motion judgment unit 202-3 indicates motion, the region judgment unit 203-2 judges the pixel which is the object of specifying the region in the frame #n belongs to the moving region, and sets the moving region judgment flag corresponding to the judged pixel in the region, to “1”, which indicates that the pixel belongs to the moving region.

[0412] In the event that the still/motion judgment supplied from the still/motion judgment unit 202-2 indicates “still”, or the still/motion judgment supplied from the still/motion judgment unit 202-3 indicates “still”, the region judgment unit 203-2 judges that the pixel which is the object of specifying the region in the frame #n does not belong to the moving region, and sets the moving region judgment flag corresponding to the judged pixel in the region, to “0”, which indicates that the pixel does not belong to the moving region.

[0413] The region judgment unit 203-2 supplies the moving region judgment flag which has been set to “1” or “0”, to the judgment flag storing frame memory 204.

[0414] In the event that the still/motion judgment supplied from the still/motion judgment unit 202-3 indicates motion, and the still/motion judgment supplied from the still/motion judgment unit 202-4 indicates “still”, the region judgment unit 203-3 judges that the pixel which is the object of specifying the region in the frame #n belongs to the covered background region, and sets the covered background region judgment flag corresponding to the judged pixel in the region to “1”, which indicates that the pixel belongs to the covered background region.

[0415] In the event that the still/motion judgment supplied from the still/motion judgment unit 202-3 indicates “still”, or the still/motion judgment supplied from the still/motion judgment unit 202-4 indicates motion, the region judgment unit 203-3 judges that the pixel which is the object of specifying the region in the frame #n does not belong to the covered background region, and sets the covered background region judgment flag corresponding to the judged pixel in the region to “0”, which indicates that the pixel does not belong to the covered background region.

[0416] The region judgment unit 203-3 supplies the covered background region judgment flag which has been set to “1” or “0” as described above, to the judgment flag storing frame memory 204.

[0417] The judgment flag storing frame memory 204 stores the uncovered background region judgment flag supplied from the region judgment unit 203-1, the still region judgment flag supplied from the region judgment unit 203-2, the moving region judgment flag supplied from the region judgment unit 203-2, and the covered background region judgment flag supplied from the region judgment unit 203-3.

[0418] The judgment flag storing frame memory 204 supplies the uncovered background region judgment flag, the still region judgment flag, the moving region judgment flag, and the covered background region judgment flag, which are stored therein, to a synthesizing unit 205. The synthesizing unit 205 generates the region information which indicates which of the uncovered background region, the still region, the moving region, or the covered background region, each pixel belongs to, and supplies the information to judgment flag storing frame memory 206, based upon the uncovered background region judgment flag, the still region judgment flag, the moving region judgment flag, and the covered background region judgment flag, which are supplied from the judgment flag storing frame memory 204.

[0419] The judgment flag storing frame memory 206 stores the region information supplied from the synthesizing unit 205, and also outputs the stored region information.

[0420] An example for processing performed by the region specifying unit 103 will now be described with reference to FIG. 33 through FIG. 37.

[0421] In the event that the object corresponding to the foreground moves, the position of the image corresponding to the object on the screen changes with each frame. As shown in FIG. 33, in the frame #n, the image corresponding to the object which is at the position indicated by Yn(x,y) is at the position Yn+1(x,y) in the following frame #n+1.

[0422] FIG. 34 is a model diagram wherein the pixel values of pixels of the image corresponding to the foreground object, which are adjacently arrayed in sequence in a image movement direction, develop over the time direction. For example, in the event that the image moving direction corresponding to the foreground object is horizontal to the screen, the model diagram in FIG. 34 indicates the model wherein the pixel values of adjacent pixels in one line develop over the time direction.

[0423] In FIG. 34, the line in the frame #n is the same as the line in the frame #n+1.

[0424] The foreground components corresponding to the object, which are included in the second pixel through thirteenth pixel from the left in the frame #n, are included in the sixth through seventeenth pixels from the left in the frame #n+1.

[0425] In the frame #n, the pixels belonging to the covered background region are the eleventh through thirteenth pixels from the left, and the pixels belonging to the uncovered background region are the second through fourth pixels from the left. In the frame #n+1, the pixels belonging to the covered background region are the fifteenth through seventeenth pixels from the left, and the pixels belonging to the uncovered background region are sixth through eighth pixels from the left.

[0426] With the example shown in FIG. 34, the movement amount v is 4, since the foreground components included in the frame #n move by four pixels in the frame #n+1. The virtual dividing number is 4, corresponding to the movement value v.

[0427] Next, a description will be made regarding the change of the pixel values of the pixels belonging to the mixed region in the frames previous to and following the frame of interest.

[0428] In the frame #n wherein the background keeps still and the movement amount v of the foreground is 4, shown in FIG. 35, the pixels belonging to the covered background region are the fifteenth through seventeenth pixels from the left. Since the movement amount v is 4, in the previous frame #n−1, the fifteenth through seventeenth pixels from the left include only the background components, and belong to the background region. Also, in the frame # n−2 which is one further before, the fifteenth through seventeenth pixels from the left contain only the background components, and belong to the background region.

[0429] Note that since the object corresponding to the background keeps still, the pixel value of the fifteenth pixel from the left in the frame #n−1 do not change from the pixel value of the fifteenth pixel from the left in the frame #n−2. Similarly, the pixel value of the sixteenth pixel from the left in the frame #n−1 do not change from the pixel value of the sixteenth pixel from the left in the frame #n−2, and the pixel values of the seventeenth pixel from the left in the frame #n−1 do not change from the pixel value of the seventeenth pixel from the left in the frame #n−2.

[0430] That is to say, the pixels of the frame #n−1 and frame #n−2 corresponding to the pixels belonging to the covered background region in the frame #n consists of only the background components, and the pixel values do not change, and accordingly the absolute value of the difference therebetween is approximately zero. Accordingly, judgment is made that the still/motion judgment for the pixels of the frame #n−1 and the frame #n−2 corresponding to the pixels belonging to the mixed region in the frame #n is still by the still/motion judgment unit 202-4.

[0431] Since the pixels belonging to the covered background region in the frame #n contain the foreground components, the pixel values are different from the case wherein the pixel values in the frame #n−1 consist of only the background components. Accordingly, judgment is made that the still/motion judgment for the pixels belonging to the mixed region in the frame #n and the pixels in the frame #n−1 corresponding thereto is motion by the still/motion judgment unit 202-3.

[0432] As described above, the region judgment unit 203-3 judges that the corresponding pixels belong to the covered background region in the event that the still/motion judgment unit 202-3 supplies the results of the still/motion judgment which indicates motion, and the still/motion judgment unit 202-4 supplies the results of the still/motion judgment which indicates “still”.

[0433] In the frame #n wherein the background keeps still and the foreground movement amount v is 4 as shown in FIG. 36, the pixels included in the uncovered background region are the second through fourth pixels from the left. Since the movement amount v is 4, in the frame #n+1 following the frame #n, the second through fourth pixels from the left include only the background components, and belong to the background region. Also, in the frame #n+2 further one frame following the frame #n+1, the second through fourth pixels from the left contain only the background components, and belong to the background region.

[0434] Note that since the object corresponding to the background keeps still, the pixel values of the second pixel from the left in the frame #n+2 does not change from the pixel value of the second pixel from the left in the frame #n+1. Similarly, the pixel value of the third pixel from the left in the frame #n+2 does not change from the pixel value of the third pixel from the left in the frame #n+1, and the pixel value of the fourth pixel from the left in the frame #n+2 does not change from the pixel value of the fourth pixel from the left in the frame #n+1.

[0435] That is to say, the pixels of the frame #n+1 and the frame #n+2, corresponding to the pixels belonging to the uncovered background region in the frame #n, consist of only the background components, so the pixel values thereof do not change, and accordingly the absolute value of the difference thereof is approximately zero. Accordingly, judgment is made that the still/motion judgment for the pixels of the frame #n+1 and the frame #n+2 corresponding to the pixels belonging to the mixed region in the frame #n is “still” by the still/motion judgment unit 202-1.

[0436] Since the pixels belonging to the uncovered background region in the frame #n contain the foreground components, the pixel values are different from the case wherein the pixels consists of only the background components in the frame #n+1. Accordingly, judgment is made that the still/motion judgment for the pixels belonging to the mixed region in the frame #n and the pixels corresponding thereto in the frame #n+1 is motion by the still/motion judgment unit 202-2.

[0437] As described above, the region judgment unit 203-1 judges that the corresponding pixels belong to the uncovered background region in the event that the still/motion judgment unit 202-2 supplies the results of the still/motion judgment which indicates motion, and the still/motion judgment unit 202-1 supplies the still/motion judgment which indicates “still”.

[0438] FIG. 37 is a diagram which illustrates judgment conditions of the region specifying unit 103 in the frame #n. In the event that judgment is made that the pixel in the frame #n−2 at the same position as the position of the pixel which is the object of judgment on the image in the frame #n, and the pixel in the frame #n−1 at the same position as the position of the pixel which is the object of judgment on the image in the frame #n, are “still”, and judgment is made that the pixel in the frame #n−1 at the same position as the position of the pixel which is the object of judgment on the image in the frame #n, and the pixel in the frame #n are motion, the region specifying unit 103 judges that the pixel which is the object of judgment of the frame #n belongs to the covered background region.

[0439] In the event that judgment is made that the pixel in the frame #n−1 at the same position as the position of the pixel which is the object of judgment on the image in the frame #n, and the pixel in the frame #n, are judged to be “still”, and judgment is made that the pixel in the frame #n and the pixel in the frame #n+1 at the same position as the position of the pixel which is the object of judgment on the image in the frame #n, are judged to be “still”, the region specifying unit 103 judges that the pixel which is the object of judgment of the frame #n belongs to the still region.

[0440] In the event that judgment is made that the pixel in the frame #n−1 at the same position as the position of the pixel which is the object of judgment on the image in the frame #n, and the pixel in the frame #n, are judged to be motion, and judgment is made that the pixel of the frame #n and the pixel in the frame #n+1 at the same position as the position of the pixel which is the object of judgment on the image in the frame #n, are judged to be motion, the region specifying unit 103 judges that the pixel which is the object of judgment of the frame #n belongs to the movement region.

[0441] In the event that judgment is made that the pixel of the frame #n and the pixel in the frame #n+1 at the same position as the position of the pixel which is the object of judgment on the image in the frame #n, are motion, and judgment is made that the pixel in the frame #n+1 at the same position as the position of the pixel which is the object of judgment on the image in the frame #n, and the pixel in the frame #n+2 at the same position as the position of the pixel which is the object of judgment on the image in the frame #n, are judged to be “still”, the region specifying unit 103 judges that the pixel which is the object of judgment of the frame #n belongs to the uncovered background region.

[0442] FIG. 38A through FIG. 38D are diagrams which illustrate examples of results of the region specifying unit 103 specifying the region. In FIG. 38A, the pixels which have been judged to belong to the covered background region are displayed in white. In FIG. 38B, the pixels which have been judged to belong to the uncovered background region are displayed in white.

[0443] In FIG. 38C, the pixels which have been judged to belong to the movement region are displayed in white. In FIG. 38D, the pixels which have been judged to belong to the still region are displayed in white.

[0444] FIG. 39 is a diagram which illustrates the region information as an image, indicating the mixed region of the region information which the judgment flag storing frame memory 206 outputs. In FIG. 39, the pixels which have been judged to belong to the covered background region or the uncovered background region, i.e., the pixels judged to belong to the mixed region, are displayed in white. The region information indicating the mixed region, which the judgment flag storing frame memory 206 outputs, indicates the mixed region and the portions which have texture within the foreground region and are surrounded by portions which have no texture.

[0445] Next, referring to the flowchart in FIG. 40, the processing for region specifying by the region specifying unit 103 will be described. In Step S201, the frame memory 201 obtains the images of the frame #n−2 through the frame #n+2, including the frame #n which is the object of judgment.

[0446] In Step S202, the still/motion judgment unit 202-3 judges whether or not the pixel of the frame #n−1 and the pixel of the frame #n at the same position keep still, and in the event of judgment of “still”, the flow proceeds to Step S203, and the still/motion judgment unit 202-2 judges whether or not the pixel of the frame #n and the pixel of the frame #n+1 at the same position keep still.

[0447] In Step S203, in the event that judgment is made that the pixel of the frame #n and the pixel of the frame #n+1 at the same position are “still”, the flow proceeds to Step S204, and the region judgment unit 203-2 sets the still region judgment flag corresponding to the judged pixel in the region to “1” which indicates the pixel belongs to the still region. The region judgment unit 203-2 supplies the still region judgment flag to the judgment flag storing frame memory 204, and the procedure proceeds to Step S205.

[0448] In Step S202, in the event that judgment is made that the pixel of the frame #n−1 and the pixel of the frame #n at the same position are motion, or in Step S203, judgment is made that the pixel of the frame #n and the pixel of the frame #n+1 at the same position are motion, the pixel of the frame #n does not belong to the still region, and accordingly the processing in Step S204 is skipped, and the procedure proceeds to Step S205.

[0449] In Step S205, the still/motion judgment unit 202-3 judges whether or not the pixel of the frame #n−1 and the pixel of the frame #n at the same position are in motion, and in the event of judgment of motion, the flow proceeds to Step S206, and the still/motion judgment unit 202-2 judges whether or not the pixel of the frame #n and the pixel of the frame #n+1 at the same position are in motion.

[0450] In Step S206, in the event that judgment is made that the pixel of the frame #n and the pixel of the frame #n+1 at the same position are in motion, the flow proceeds to Step S207, the region judgment unit 203-2 set the movement region judgment flag corresponding to the judged pixel in the region to “1” which indicates that the pixel belongs to the movement region. The region judgment unit 203-2 supplies the movement region judgment flag to the judgment flag storing frame memory 204, and the procedure proceeds to Step S208.

[0451] In Step S205, in the event that judgment is made that the pixel of the frame #n−1 and the pixel of the frame #n at the same position are “still”, or in Step S206, in the event that judgment is made that the pixel of the frame #n and the pixel of the frame #n+1 at the same position are “still”, since the pixel of the frame #n does not belong to the movement region, the processing in Step S207 is skipped, and the procedure proceeds to Step S208.

[0452] In Step S208, the still/motion judgment unit 202-4 judges whether or not the pixel of the frame #n−2 and the pixel of the frame #n−1 at the same position keeps still, and in the event of judgment of “still”, the flow proceeds to Step S209, and the still/motion judgment unit 202-3 judges whether or not the pixel of the frame #n−1 and the pixel of the frame #n at the same position are in motion.

[0453] In Step S209, in the event that judgment is made that the pixel of the frame #n−1 and the pixel of the frame #n at the same position are in motion, the flow proceeds to Step S210, and the region judgment unit 203-3 sets the covered background region judgment flag corresponding to the judged pixel in the region to “1” which indicates that the pixel belongs to the covered background region. The region judgment unit 203-3 supplies the covered background region judgment flag to the judgment flag storing frame memory 204, and the procedure proceeds to Step S211.

[0454] In Step S208, in the event that judgment is made that the pixel of the frame #n−2 and the pixel of the frame #n−1 at the same position are in motion, or in Step S209, in the event that judgment is made that the pixel of the frame #n−1 and the pixel of the frame #n at the same position are “still”, the pixel of the frame #n does not belong to the covered background region, so the processing in Step S210 is skipped, and the procedure proceeds to Step S211.

[0455] In Step S211, the still/motion judgment unit 202-2 judges whether or not the pixel of the frame #n and the pixel of the frame #n+1 at the same position are in motion, and in the event of judgment of motion, the flow proceeds to Step S212, and the still/motion judgment unit 202-1 judges whether or not the pixel of the frame #n+1 and the pixel of the frame #n+2 at the same position keep still.

[0456] In Step S212, in the event that judgment is made that the pixel of the frame #n+1 and the pixel of the frame #n+2 at the same position are “still”, the flow proceeds to Step S213, and the region judgment unit 203-1 sets the uncovered background region judgment flag corresponding to the judged pixel in the region to “1” which indicates that the pixel belongs to the uncovered background region. The region judgment unit 203-1 supplies the uncovered background region judgment flag to the judgment flag storing frame memory 204, and the procedure proceeds to Step S214.

[0457] In Step S211, in the event that judgment is made that the pixel of the frame #n and the pixel of the frame #n+1 at the same position are “still”, or in Step 212, in the event that judgment is made that the pixel of the frame #n+1 and the pixel of the frame #n+2 at the same position are in motion, since the pixel of the frame #n does not belong to the uncovered background region, the processing in Step S213 is skipped, and the procedure proceeds to Step S214.

[0458] In Step S214, the region specifying unit 103 judges whether or not all the pixels in the frame #n are region-specified, and in the event that judgment is made that not all pixels are region-specified, the procedure returns to Step S202, and repeats the processing of specifying the region for other pixels.

[0459] In Step S214, in the event that judgment is made that all the pixels in the frame #n are region-specified, the flow proceeds to Step S215, and the synthesizing unit 205 generates the region information which indicates the mixed region based upon the uncovered background region judgment flag and the covered background region judgment flag, which are stored in the judgment flag storing frame memory 204, and furthermore generates the region information which indicates which of the uncovered background region, the still region, the movement region, or the covered background region, each pixel belongs to, sets the generated region information for the judgment flag storing frame memory 206, and the processing ends.

[0460] As described above, the region specifying unit 103 can generate region information which indicates which of the movement region, the still region, the uncovered background region, or the covered background region, each pixel contained in the frame belongs to.

[0461] Note that an arrangement may be made wherein the region specifying unit 103 generates the region information corresponding to the mixed region and the region information made up of flags which indicates which of the movement region, the still region, or the mixed region, each of pixels contained in the frame belongs to, by applying the logical sum to the region information corresponding to the uncovered background region and the covered background region.

[0462] In the event that the object corresponding to the foreground has texture, the region specifying unit 103 can specify the movement region more accurately.

[0463] The region specifying unit 103 can output the region information indicating the movement region as the region information indicating the foreground region, or output the region information indicating the still region as the region information indicating the background region.

[0464] While description has been made wherein the object corresponding to the background keeps still, the processing of specifying the region described above can be applied even if the image corresponding to the background region contains motion. For example, in the event that the image corresponding to the background region moves in a constant manner, the region specifying unit 103 shifts the entire image corresponding to the movement, and performs processing in the same manner as with the case wherein the object corresponding to the background keeps still. Also, in the event that the image corresponding to the background region contains a different motion at each local position, the region specifying unit 103 selects the pixel corresponding to the motion, and performs the above-described processing.

[0465] FIG. 41 is a block diagram which illustrates another example of the structure of the region specifying unit 103. The region specifying unit 103 shown in FIG. 41 does not use movement vectors. A background image generating unit 301 generates the background image corresponding to the input image, and supplies the generated background image to a binary object image extracting unit 302. The background image generating unit 301 extracts, for example, the image object corresponding to the background object contained in the input image, and generates the background image.

[0466] An example of a model diagram is illustrated in FIG. 42 wherein the pixel values of the pixels arrayed in sequence adjacently in a movement direction of the image corresponding to the foreground object develop over the time direction. For example, the model diagram in FIG. 42 illustrates a model wherein, in the event that the movement direction of the image corresponding to the foreground object is horizontal to the screen, the pixel values of the adjacent pixels in one line develop over the time direction.

[0467] In FIG. 42, the line in the frame #n is the same as the line in the frame #n−1 and the line in the frame #n+1.

[0468] In the frame #n, the foreground components corresponding to the object, which are contained in the sixth pixel through seventeenth pixel from the left, are contained in the second through thirteenth pixels from the left in the frame #n−1, and are contained in the tenth through twenty first pixels from the left in the frame #n+1.

[0469] In the frame #n−1, the pixels belonging to the covered background region are the eleventh through thirteenth pixels from the left, and the pixels belonging to the uncovered background region are the second through fourth pixels from the left. In the frame #n, the pixels belonging to the covered background region are the fifteenth through the seventeenth pixels from the left, and the pixels belonging to the uncovered background region are the sixth through eighth pixels from the left. In the frame #n+1, the pixels belonging to the covered background region are the nineteenth through twenty first pixels from the left, and the pixels belonging to the uncovered background region are the tenth through twelfth pixels from the left.

[0470] In the frame #n−1, the pixels belonging to the background region are the first from the left, and the fourteenth through twenty first pixels from the left. In the frame #n, the pixels belonging to the background region are the first through fifth pixels from the left, and the eighteenth through twenty first pixels from the left. In the frame #n+1, the pixels belonging to the background region are the first through ninth pixels from the left.

[0471] An example of the background image corresponding to the example shown in FIG. 42, which is generated by the background image generating unit 301, is illustrated in FIG. 43. The background image is made up of the pixels corresponding to the background object, and does not contain image components corresponding to the foreground object.

[0472] The binary object image extracting unit 302 generates a binary object image based upon the correlation between the background image and the input image, and supplies the generated binary object image to a time change detecting unit 303.

[0473] FIG. 44 is a block diagram which illustrates the configuration of the binary object image extracting unit 302. A correlation value computing unit 321 computes the correlation between the background image supplied from the background image generating unit 301 and the input image, generates a correlation value, and supplies the generated correlation value to a threshold value processing unit 322.

[0474] The correlation value computing unit 321 applies Expression (4) to a block 3×3 wherein X₄ is centered in the background image as shown in FIG. 45A, and a block 3×3 wherein Y₄ corresponding to the block in the background image is centered in the input image as shown in FIG. 45B, and calculates a correlation value corresponding to the Y₄, for example.

[0475] $\begin{array}{cc}\mathrm{Correlation}\mathrm{Value}=\frac{\sum _{i=0}^8\left(X_i-\stackrel{\_}{X}\right)\sum _{i=0}^8\left(Y_i-\stackrel{\_}{Y}\right)}{\sqrt{\sum _{i=0}^8{\left(X_i-\stackrel{\_}{X}\right)}^2·\sum _{i=0}^8{\left(Y_i-\stackrel{\_}{Y}\right)}^2}}& \left(4\right)\\ \stackrel{\_}{X}=\frac{\sum _{i=0}^8{X}_i}{9}& \left(5\right)\\ \stackrel{\_}{Y}=\frac{\sum _{i=0}^8{Y}_i}{9}& \left(6\right)\end{array}$

[0476] The correlation value computing unit 321 supplies the correlation value calculated corresponding to each pixel as described above to the threshold value processing unit 322.

[0477] Also, an arrangement may be made wherein the correlation value computing unit 321, for example, applies Expression (7) to the block 3×3 in the background image wherein X₄ is centered as shown in FIG. 46A, and the block 3×3 in the input image wherein Y₄ is centered corresponding to the block in the background image as shown in FIG. 46B, and calculates the sum of absolute value of difference corresponding to Y₄.

[0478] $\begin{array}{cc}\mathrm{Sum}\mathrm{of}\mathrm{Absolute}\mathrm{Value}\mathrm{of}\mathrm{Difference}=\sum _{i=0}^8\left(X_i-Y_i\right)& \left(7\right)\end{array}$

[0479] The correlation value computing unit 321 supplies the difference absolute value calculated as described above as the correlation value to the threshold value processing unit 322.

[0480] The threshold value processing unit 322 compares the pixel value of the correlation image with the threshold value th0, and in the event that the correlation value is equal to or less than the threshold value th0, the threshold value processing unit 322 sets the pixel value of the binary object image to 1, and in the event that the correlation value is greater than the threshold value th0, the threshold value processing unit 322 sets the pixel value of the binary object image to 0, and outputs the binary object image of which each pixel value has been set to 0 or 1. The threshold value processing unit 322 may store the threshold value th0 beforehand, and may use the threshold value th0 which is input externally.

[0481] FIG. 47 is a diagram which illustrates an example of the binary object image corresponding to the model of the input image shown in FIG. 42. In the binary object image, a pixel value of a pixel having a high correlation with the background image is set to 0.

[0482] FIG. 48 is a block diagram which illustrates the configuration of the time change detecting unit 303. Frame memory 341 stores the binary object images of the frame #n−1, frame #n, and frame #n+1, supplied from the binary object image extracting unit 302 at the point of judgment of the region for the pixel of the frame #n.

[0483] A region judgment unit 342 judges the region for each pixel of the frame #n based upon the binary object images of the frame #n−1, frame #n, and frame #n+1, which are stored in the frame memory 341, generates the region information, and outputs the generated region information.

[0484] FIG. 49 is a diagram which describes the judgment made by the region judgment unit 342. In the event that the pixel of interest of the binary object image of the frame #n is 0, the region judgment unit 342 judges the pixel of interest of the frame #n to belong to the background region.

[0485] In the event that the pixel of interest of the binary object image of the frame #n is 1, the corresponding pixel of the binary object image of the frame #n−1 is 1, and the corresponding pixel of the binary object image of the frame #n+1 is 1, the region judgment unit 342 judges the pixel of interest of the frame #n to belong to the foreground region.

[0486] In the event that the pixel of interest of the binary object image of the frame #n is 1, and the corresponding pixel of the binary object image of the frame #n−1 is 0, the region judgment unit 342 judges the pixel of interest of the frame #n to belong to the covered background region.

[0487] In the event that the pixel of interest of the binary object image of the frame #n is 1, and the corresponding pixel of the binary object image of the frame #n+1 is 0, the region judgment unit 342 judges the pixel of interest of the frame #n to belong to the uncovered background region.

[0488] FIG. 50 is a diagram which illustrates an example wherein the time change detecting unit 303 judges the binary object image corresponding to the model of the input image shown in FIG. 42. The time change detecting unit 303 judges the first through fifth pixels from the left of the frame #n to belong to the background region since the corresponding pixels of the binary object image of the frame #n are 0.

[0489] The time change detecting unit 303 judges the sixth through ninth pixels from the left to belong to the uncovered background region since the pixels of the binary object image of the frame #n are 1, and the corresponding pixels of the frame #n+1 are 0.

[0490] The time change detecting unit 303 judges the tenth through thirteenth pixels from the left to belong to the foreground region since the pixels of the binary object image of the frame #n are 1, the corresponding pixels of the frame #n−1 are 1, and the corresponding pixels of the frame #n+1 are 1.

[0491] The time change detecting unit 303 judges the fourteenth through seventeenth pixels from the left to belong to the covered background region since the pixels of the binary object image of the frame #n are 1, and the corresponding pixels of the frame #n−1 are 0.

[0492] The time change detecting unit 303 judges the eighteenth through twenty first pixels from the left to belong to the background region since the corresponding pixels of the binary object image of the frame #n are 0.

[0493] The processing of specifying the region by the region judgment unit 103 will be now described, referring to the flowchart shown in FIG. 51. In Step S301, the background image generating unit 301 of the region judgment unit 103, for example, generates the background image by extracting the image object corresponding to the background object contained in the input image based upon the input image, and supplies the generated background image to the binary object image extracting unit 302.

[0494] In Step S302, the binary object image extracting unit 302 computes the correlation value between the input image and the background image supplied from the background image generating unit 301 by the computation described referring to FIG. 45, for example. In Step S303, the binary object image extracting unit 302 computes the binary object image from the correlation value and the threshold value th0 by comparing the correlation value with the threshold value th0, for example.

[0495] In Step S304, the time change detecting unit 303 performs processing of region judgment, and the processing ends.

[0496] The processing of the region judgment corresponding to Step S304 will be described in detail, referring to the flowchart shown in FIG. 52. In Step S321, the region judgment unit 342 of the time change detecting unit 303 judges whether or not the pixel of interest in the frame #n stored in the frame memory 341 is 0, and in the event that the judgment is made that the pixel of the interest in the frame #n is 0, the flow proceeds to Step S322, makes settings to the effect that the pixel of interest in the frame #n belongs to the background region, and the processing ends.

[0497] In Step S321, in the event that judgment is made that the pixel of interest in the frame #n is 1, the flow proceeds to Step S323, and the region judgment unit 342 of the time change detecting unit 303 judges whether or not the pixel of interest in the frame #n stored in the frame memory 341 is 1, and the corresponding pixel in the frame #n−1 is 0, and in the event that judgment is made that the pixel of interest in the frame #n is 1, and the corresponding pixel in the frame #n−1 is 0, the flow proceeds to Step S324, makes settings to the effect that the pixel of interest in the frame #n belongs to the covered background region, and the processing ends.

[0498] In Step S323, in the event that judgment is made that the pixel of interest in the frame #n is 0, or the corresponding pixel in the frame #n−1 is 1, the flow proceeds to Step S325, and the region judgment unit 342 of the time change detecting unit 303 judges whether or not the pixel of interest in the frame #n stored in the frame memory 341 is 1, and the corresponding pixel in the frame #n+1 is 0, and in the event that judgment is made that the pixel of interest in the frame #n is 1, and the corresponding pixel in the frame #n+1 is 0, the flow proceeds to Step S326, makes settings to the effect that the pixel of interest in the frame #n belongs to the uncovered background region, and the processing ends.

[0499] In Step S325, in the event that judgment is made that the pixel of interest in the frame #n is 0, or the corresponding pixel in the frame #n+1 is 1, the flow proceeds to Step S327, and the region judgment unit 342 of the time change detecting unit 303 sets the pixel of interest in the frame #n for the foreground region, and the processing ends.

[0500] As described above, the region specifying unit 103 can specify which of the foreground region, the background region, the covered background region, or the uncovered background region, the pixel of the input image belongs to, and can generate region information corresponding to the specified results.

[0501] FIG. 53 is a block diagram which illustrates another configuration of the region specifying unit 103. The region specifying unit 103 shown in FIG. 53 uses the movement vector and the position information thereof, which are supplied from the movement detecting unit 102. Portions the same as those shown in FIG. 41 are denoted by the same reference numerals, and description thereof will be omitted.

[0502] A robustification unit 361 generates a robustified binary object image based upon N frames of the binary object image supplied from the binary object image extracting unit 302, and outputs to the time change detecting unit 303.

[0503] FIG. 54 is a block diagram which describes the configuration of the robustification unit 361. A movement compensation unit 381 compensates for the movement of the binary object image of N frames based upon the movement vector and the position information thereof supplied from the movement detecting unit 102, and outputs the binary object image which has been subjected to compensation of movement to a switch 382.

[0504] The movement compensation of the movement compensation unit 381 will be described with reference to examples shown in FIG. 55 and FIG. 56. For example, when judging the region in the frame #n, in the event that there is input of the binary object images of the frame #n−1, the frame #n, and the frame #n+1, shown by way of the example in FIG. 55, the movement compensation unit 381 compensates for movement of the binary object image of the frame #n−1 and the binary object image of the frame #n+1, based upon the movement vector supplied from the movement detecting unit 102, and supplies the binary object image which has been subjected to compensation of movement to the switch 382, as indicated in the example shown in FIG. 56.

[0505] The switch 382 outputs the binary object image which has been subjected to movement compensation of the first frame, to the frame memory 383-1, and outputs the binary object image which has been subjected to movement compensation of the second frame to the frame memory 383-2. Similarly, the switch 382 outputs each of the binary object images of which the third through N−1'th frames have been subjected to compensation for the movement to each of frame memory 383-3 through frame memory 383-(N−1), respectively, and outputs the binary object image of which the N'th frame has been subjected to movement compensation to frame memory 383-N.

[0506] The frame memory 383-1 stores the binary object image of which the first frame has been subjected to movement compensation, and outputs the stored binary object image to a weighting addition unit 384-1. The frame memory 383-2 stores the binary object image of which the second frame has been subjected to movement compensation, and outputs the stored binary object image to a weighting addition unit 384-2.

[0507] Similarly, each of the frame memory 383-3 through the frame memory 383-(N−1) stores each of the binary object images of which one of the third frame through N−1'th frame has been subjected to compensation for the movement, and outputs the stored binary object image to each of the weighing addition unit 384-3 through the weighing addition unit 384-(N−1). The frame memory 383-N stores the binary object image of which N'th frame has been subjected to compensation for the movement, and outputs the stored binary object image to a weighing addition unit 384-N.

[0508] The weighing addition unit 384-1 multiplies the pixel value of the binary object image of which the first frame has been subjected to compensation for the movement supplied from the frame memory 383-1 by the predetermined weight w1, and supplies to an accumulation unit 385. The weighing addition unit 384-2 multiplies the pixel value of the binary object image of the second frame which has been subjected to movement compensation supplied from the frame memory 383-2 by the predetermined weight w2, and supplies to an accumulation unit 385.

[0509] Similarly, each of the weighting addition unit 384-3 through the weighing addition unit 384-(N−1) multiplies the pixel value of the binary object image of one of the third through N−1'th frames, which has been subjected to movement compensation supplied from one of the frame memory 383-3 through the frame memory 383-(N−1) by one of the predetermined weights w3 through w(N−1), and supplies to the accumulation unit 385. A weighing addition unit 384-N multiplies the pixel value of the binary object image of the N'th frame supplied from the frame memory 383-N which has been subjected to movement compensation by the predetermined weight wN, and supplies to the accumulation unit 385.

[0510] The accumulation unit 385 accumulates the pixel value corresponding to the binary object image, wherein each of the first through N'th frames which has been subjected to movement compensation is multiplied by one of the predetermined weights w1 through wN, and generates the binary object image by comparing the accumulated pixel value with the predetermined threshold value th0.

[0511] As described above, the robustification unit 361 generates the robustified binary object image from the N frames of binary object images, and supplies to the time change detecting unit 303, so the region specifying unit 103 of which the configuration is shown in FIG. 53 can specify the region more accurately as compared with the case shown in FIG. 41, even if the input image contains noise.

[0512] The processing for specifying the region of the region specifying unit 103 of which the configuration is shown in FIG. 53 will now be described, referring to the flowchart shown in FIG. 57. The processing in Step S341 through Step S343 is the same as Step S301 through Step S303 described in the flowchart shown in FIG. 51, respectively, and accordingly, description thereof will be omitted.

[0513] In Step S344, the robustification unit 361 performs processing for robustification.

[0514] In Step S345, the time change detecting unit 303 performs processing for specifying the region, and the processing ends. Details of the processing in Step S345 are the same as the processing described with reference to the flowchart shown in FIG. 52, so description thereof will be omitted.

[0515] Referring to the flowchart shown in FIG. 58, processing of robustification corresponding to the processing in Step S344 shown in FIG. 57 will now be described in detail. In Step S361, the movement compensation unit 381 performs movement compensation processing of the input binary object image based upon the movement vector and the position information thereof supplied from the movement detecting unit 102. In Step S362, one of the frame memory 383-1 through the frame memory 383-N stores the binary object image, which has been subjected to movement compensation, supplied via the switch 382.

[0516] In Step S363, the robustification unit 361 judges whether or not N binary object images are stored, and in the event that judgment is made that N binary object images have not been stored, the flow returns to Step S361, and the robustification unit 363 repeats processing of compensation for movement of the binary object image, and processing of storing the binary object image.

[0517] In Step S363, in the event that judgment is made that N binary object images stored, the flow proceeds to Step S364, and each of the weighting addition units 384-1 through 384-N multiplies each of N binary object images, by one of the weights w1 through wN for weighting.

[0518] In Step S365, the accumulation unit 385 accumulates the N weighted binary object images.

[0519] In Step S366, the accumulation unit 385 generates the binary object image from the accumulated image, by comparing with the predetermined threshold value th1, for example, and the processing ends.

[0520] As described above, the region specifying unit 103, of which the configuration is shown in FIG. 53, can generate region information based upon the robustified binary object image.

[0521] As described above, the region specifying unit 103 can generate the region information which indicates which of the movement region, the still region, the uncovered background region, or the covered background region, each of the pixels contained in the frame belongs to.

[0522] FIG. 59 is a block diagram which illustrates an example of the configuration of the mixture ratio calculating unit 104. An estimated mixture ratio processing unit 401 calculates estimated mixture ratio for each pixel by computation corresponding to a model of a covered background region based upon the input image, and supplies the calculated estimated mixture ratio to a mixture ratio determination unit 403.

[0523] An estimated mixture ratio processing unit 402 calculates estimated mixture ratio for each pixel by computation corresponding to a model of the uncovered background region based upon the input image, and supplies the calculated estimated mixture ratio to the mixture ratio determination unit 403.

[0524] Since an assumption may be made that the object corresponding to the foreground moves at a constant velocity within a shutter period, the mixture ratio α of a pixel belonging to the mixed region has a nature such as described below. That is to say, the mixture ratio α changes linearly corresponding to the change of the position of the pixel. Taking the change of the pixel position to be one-dimensional, the change of the mixture ratio α may be represented by a straight line, and taking the change of the pixel position to be two-dimensional, the change of the mixture ratio α may be represented by a plane.

[0525] Note that the period of one frame is short, an assumption may be made that the object corresponding to the foreground is a rigid body, and moves at a constant velocity.

[0526] In this case, the inclination of the mixture ratio α is inversely proportionate to the movement amount v of the foreground within the shutter period.

[0527] An example of an ideal mixture ratio α is shown in FIG. 60. The inclination 1 of an ideal mixture ratio α in the mixed region may be represented by the reciprocal of the movement amount v.

[0528] As shown in FIG. 60, an ideal mixture ratio α has a value of 1 in the background region, and has a value of 0 in the foreground region, and has a value which exceeds 0 and is less than 1 in the mixed region.

[0529] With the example shown in FIG. 61, the pixel value C06 of the seventh pixel from the left in the frame #n may be represented in Expression (8), using the pixel value P06 of the seventh pixel from the left in the frame #n−1.

[0530] $\begin{array}{cc}\begin{array}{c}C06=B06/v+B06/v+F01/v+F02/v\\ =P06/v+P06/v+F01/v+F02/v\\ =2/v·P06+\sum _{i=1}^2{F}_i/v\end{array}& \left(8\right)\end{array}$

[0531] In Expression (8), the pixel value C06 is represented as the pixel value M of the pixel in the mixed region, and the pixel value P06 is represented as the pixel value B of the pixel in the background region. That is to say, the pixel value M of the pixel in the mixed region and the pixel value B of the pixel in the background region may be represented as in Expression (9) and Expression (10), respectively.
M=C06  (9)
B=P06  (10)

[0532] In Expression (8), 2/v corresponds to the mixture ratio α. Since the movement amount v is 4, the mixture ratio α of the seventh pixel from the left in the frame #n is 0.5.

[0533] As described above, Expression (3) indicating the mixture ratio α may be rewritten as with Expression (11) by reckoning the pixel value C in the frame #n of interest to be a pixel value in the mixed region, and reckoning the pixel value P in the frame #n−1 previous to the frame #n to be a pixel value of the background region.
C=α·P+f  (11)

[0534] In Expression (11), f is the sum of the foreground components contained in the pixel of interest, Σ_iFi/v. The variables included in Expression (11) are two, i.e., the mixture ratio α and the sum of the foreground components f.

[0535] In the same way, FIG. 62 illustrates a model wherein the pixel values wherein the movement amount v is 4, and virtual dividing number is 4 in the uncovered background region, develop over the time direction.

[0536] Expression (3) indicating the mixture ratio α may be represented as in Expression (12) with the pixel value C in the frame #n of interest as a pixel value in the mixed region, and with the pixel value N in the frame #n+1 following the frame #n as a pixel value in the background region, in the same manner as the representation in the covered background region described above, in the uncovered background region.
C=α·N+f  (12)

[0537] Note that while description has been made with an assumption that the background object keeps still, Expression (8) through Expression (12) may be applied by using the pixel values of the pixels at the positions corresponding to the background movement amount v, even if the background object moves. For example, in FIG. 61, in the event that the movement amount v of the object corresponding to the background is 2, the virtual dividing number is 2, and the object corresponding to the background moves to the right side in the drawing, the pixel value B of the pixel in the background region in Expression (10) is the pixel value P04.

[0538] Expression (11) and Expression (12) include two variables, respectively, and accordingly the mixture ratio α can not be obtained in this state. Here, images generally have great correlation spatially, the adjacent pixels have approximately the same value.

[0539] Thus, since the foreground components have great correlation spatially, the mixture ratio is obtained by transforming the expression so as to obtain the sum of the foreground components from the previous or following frame.

[0540] The pixel value Mc of the seventh pixel from the left in the frame #n in FIG. 63 may be represented in Expression (13).

[0541] $\begin{array}{cc}\mathrm{Mc}=\frac{2}{v}·B06+\sum _{i=11}^{12}{F}_i/v& \left(13\right)\end{array}$

[0542] The first argument 2/v of the right side in Expression (13) corresponds to the mixture ratio α. The second argument of the right side in Expression (13) is represented as in Expression (14) using the pixel values in the following frame #n+1.

[0543] $\begin{array}{cc}\sum _{i=11}^{12}{F}_i/v=\beta ·\sum _{i=7}^{10}{F}_i/v& \left(14\right)\end{array}$

[0544] Here, an assumption may be made that Expression (15) holds, using the spatial correlation of the foreground components.
F=F05=F06=F07=F08=F09=F10=F11=F12  (15)

[0545] Expression (14) may be rewritten as Expression (16) using Expression (15).

[0546] $\begin{array}{cc}\begin{array}{c}\sum _{i=11}^{12}{F}_i/v=\frac{2}{v}·F\\ =\beta ·\frac{4}{v}·F\end{array}& \left(16\right)\end{array}$

[0547] As a result, β may be represented in Expression (17).
β=2/4  (17)

[0548] In general, in the event that an assumption is made wherein the foreground components correlated to the mixed region are the same as shown in Expression (15), Expression (18) is formed by the relationship of the internal dividing ratio for all the pixel in the mixed region.
β=1−α  (18)

[0549] In the event that Expression (18) holds, Expression (11) may develop as indicated in Expression (19).

[0550] $\begin{array}{cc}\begin{array}{c}C=\alpha ·P+f\\ =\alpha ·P+\left(1-\alpha \right)·\sum _{i=\gamma }^{\gamma +V-1}{F}_i/v\\ =\alpha ·P+\left(1-\alpha \right)·N\end{array}& \left(19\right)\end{array}$

[0551] Similarly, in the event that Expression (18) holds, Expression (12) may develop as indicated in Expression (20).

[0552] $\begin{array}{cc}\begin{array}{c}C=\alpha ·N+f\\ =\alpha ·N+\left(1-\alpha \right)·\sum _{i=\gamma }^{\gamma +V-1}{F}_i/v\\ =\alpha ·N+\left(1-\alpha \right)·P\end{array}& \left(20\right)\end{array}$

[0553] In Expression (19) and Expression (20), since C, N, and P are known pixel values, the variable included in Expression (19) and Expression (20) is only the mixture ratio α. The relationship between C, N, and P in Expression (19) and Expression (20) is illustrated in FIG. 64. C is the pixel value of the pixel of interest in the frame #n for calculating the mixture ratio α. N is the pixel value of the pixel in the frame #n+1, of which the position in the spatial direction corresponds to that of the pixel of interest. P is the pixel value of the pixel in the frame #n−1, of which the position in the spatial direction corresponds to that of the pixel of interest.

[0554] Accordingly, since Expression (19) and Expression (20) include one variable each, the mixture ratio α can be calculated using the pixel values in three frames. The conditions for calculating an accurate mixture ratio α by solving Expression (19) and Expression (20) are that; the foreground components with regard to the mixed region are the same, that is to say, in the foreground image object which has been taken in the state of the foreground object being still, the pixel values of pixels of a number double the movement amount v, which are arrayed sequentially at the boundary of the image object, corresponding to the movement direction of the foreground object, are constant.

[0555] As described above, the mixture ratio α of the pixel belonging to the covered background region is calculated by Expression (21), and the mixture ratio α belonging to the uncovered background region is calculated by Expression (22).
α=(C−N)/(P−N)  (21)
α=(C−P)/(N−P)  (22)

[0556] FIG. 65 is a block diagram which illustrates the configuration of the estimated mixture ratio processing unit 401. Frame memory 421 stores the input image in increments of frames, and supplies the frame following the frame which is input as an input image, to frame memory 422 and a mixture ratio computation unit 423.

[0557] The frame memory 422 stores the input image in increments of frames, and supplies the frame following the frame supplied from the frame memory 421, to the mixture ratio computation unit 423.

[0558] Accordingly, in the event that the frame #n+1 is input as an input image to the mixture ratio computation unit 423, the frame memory 421 supplies the frame #n to the mixture ratio computation unit 423, and the frame memory 422 supplies the frame #n−1 to the mixture ratio computation unit 423.

[0559] The mixture ratio computation unit 423 calculates the estimated mixture ratio of the pixel of interest by the computation represented in Expression (21) based upon the pixel value C of the pixel of interest in the frame #n, the pixel value N of the pixel in the frame #n+1 wherein the spatial position thereof corresponds to that of the pixel of interest, and the pixel value P of the pixel in the frame #n−1 wherein the spatial position thereof corresponds to that of the pixel of interest, and outputs the calculated estimated mixture ratio. For example, in the event that the background keeps still, the mixture ratio computation unit 423 calculates the estimated mixture ratio of the pixel of interest based upon the pixel value C of the pixel of interest in the frame #n, the pixel value N of the pixel in the frame #n+1 at the same position in the frame as the pixel of interest, and the pixel value P of the pixel in the frame #n−1 at the same position in the frame as the pixel of interest, and outputs the calculated estimated mixture ratio.

[0560] As described above, the estimated mixture ratio processing unit 401 can calculate the estimated mixture ratio based upon the input image, and supply to the mixture ratio decision unit 403.

[0561] Note that the processing of the estimated mixture ratio processing unit 402 is the same as that of the estimated mixture ratio processing unit 401 except for the processing wherein, while the estimated mixture ratio processing unit 401 calculates the estimated mixture ratio of the pixel of interest by the computation represented in Expression (21), the estimated mixture ratio processing unit 402 calculates the estimated mixture ratio of the pixel of interest by the computation represented in Expression (22), and accordingly, description thereof will be omitted.

[0562] FIG. 66 is a diagram which illustrates an example of the estimated mixture ratio calculated by the estimated mixture ratio processing unit 401. The estimated mixture ratio shown in FIG. 66 indicates the results in a case wherein the foreground movement amount v corresponding to the object which moves at a constant velocity is 11, for one line.

[0563] It can be understood that the estimated mixture ratio changes generally linearly in the mixed region, as shown in FIG. 60.

[0564] Returning to FIG. 59, the mixture ratio decision unit 403 sets the mixture ratio α based upon the region information indicating which of the foreground region, the background region, the covered background region, or the uncovered background region, the pixel which is the object of calculation of the mixture ratio α belongs to, supplied from the region specifying unit 103.

[0565] In the event that the pixel which is the object belongs to the foreground region, the mixture ratio decision unit 403 sets the mixture ratio α to 0, in the event that the pixel which is the object belongs to the background region, sets the mixture ratio α to 1, in the event that the pixel which is the object belongs to the covered background region, sets the mixture ratio α to the estimated mixture ratio supplied from the estimated mixture ratio processing unit 401, and in the event that the pixel which is the object belongs to the uncovered background region, sets the mixture ratio α to the estimated mixture ratio supplied from the estimated mixture ratio processing unit 402. The mixture ratio decision unit 403 outputs the mixture ratio α which has been set based upon the region information.

[0566] FIG. 67 is a block diagram which illustrates another configuration of the mixture ratio calculating unit 104. A selection unit 441 supplies the pixels belonging to the covered background region and the corresponding pixels in the following and previous frames, to an estimated mixture ratio processing unit 442, based upon the region information supplied from the region specifying unit 103. The selection unit 441 supplies the pixels belonging to the uncovered background region and the corresponding pixels in the previous and following frames, to an estimated mixture ratio processing unit 443, based upon the region information supplied from the region specifying unit 103.

[0567] The estimated mixture ratio processing unit 442 calculates the estimated mixture ratio of the pixel of interest belonging to the covered background region by the computation represented in Expression (21) based upon the pixel values input from the selection unit 441, and supplies the calculated estimated mixture ratio to a selection unit 444.

[0568] The estimated mixture ratio processing unit 443 calculates the estimated mixture ratio of the pixel of interest belonging to the uncovered background region by the computation represented in Expression (22) based upon the pixel values input from the selection unit 441, and supplies the calculated estimated mixture ratio to the selection unit 444.

[0569] In the event that the pixel which is the object belongs to the foreground region, the selection unit 444 selects the estimated mixture ratio of 0, and sets for the mixture ratio α, and in the event that the pixel which is the object belongs to the background region, the selection unit 444 selects the estimated mixture ratio of 1, and sets for the mixture ratio α, based upon the region information supplied from the region specifying unit 103. In the event that the pixel which is the object belongs to the covered background region, the selection unit 444 selects the estimated mixture ratio supplied from the estimated mixture ratio processing unit 442, and sets for the mixture ratio α, and in the event that the pixel which is the object belongs to the uncovered background region, the selection unit 444 selects the estimated mixture ratio supplied from the estimated mixture ratio processing unit 443, and sets this for the mixture ratio α. The selection unit 444 outputs the mixture ratio α which has been selected and set based upon the region information.

[0570] As described above, the mixture ratio calculating unit 104 having another configuration shown in FIG. 67 can calculate the mixture ratio α for each pixel contained in the image, and output the calculated mixture ratio α.

[0571] Referring to the flowchart shown in FIG. 68, the processing for calculation of the mixture ratio α by the mixture ratio calculating unit 104 of which configuration is shown in FIG. 59 will be described. In Step S401, the mixture ratio calculating unit 104 obtains the region information supplied from the region specifying unit 103. In Step S402, the estimated mixture ratio processing unit 401 performs processing of computation of the estimated mixture ratio by a model corresponding to the covered background region, and supplies the calculated estimated mixture ratio to the mixture ratio decision unit 403. Details of the processing for computation of the estimated mixture ratio will be described later with reference to the flowchart shown in FIG. 69.

[0572] In Step S403, the estimated mixture ratio processing unit 402 performs the processing of the computation of the estimated mixture ratio by a model corresponding to the uncovered background region, and supplies the calculated mixture ratio to the mixture ratio decision unit 403.

[0573] In Step S404, the mixture ratio calculating unit 104 judges whether or not the mixture ratio α has been estimated for the entire frame, and in the event that judgment is made that the mixture ratio α has not been estimated for the entire frame, the flow returns to Step S402, and performs the processing of estimation of the mixture ratio α for the following pixel.

[0574] In the event that judgment is made in Step S404 that the mixture ratio α has been estimated for the entire frame, the flow proceeds to Step S405, and the mixture ratio decision unit 403 sets the mixture ratio α based upon the region information which indicates which of the foreground region, the background region, the covered background region, or the uncovered background region, the pixel belongs to, supplied from the region specifying unit 103. In the event that the pixel which is the object belongs to the foreground region, the mixture ratio decision unit 403 sets the mixture ratio α to 0, in the event that the pixel which is the object belongs to the background region, sets the mixture ratio α to 1, in the event that the pixel which is the object belongs to the covered background region, sets the mixture ratio α to the estimated mixture ratio supplied from the estimated mixture ratio processing unit 401, and in the event that the pixel which is the object belongs to the uncovered background region, sets the mixture ratio α to the estimated mixture ratio supplied from the estimated mixture ratio processing unit 402, and the processing ends.

[0575] As described above, the mixture ratio calculating unit 104 can calculate the mixture ratio α which is the amount of features corresponding to each pixel based upon the region information supplied from the region specifying unit 103 and the input image.

[0576] The processing of calculation of the mixture ratio α by the mixture ratio calculation unit 104 of which configuration is shown in FIG. 67 is the same as the processing described in the flowchart shown in FIG. 68, so description thereof will be omitted.

[0577] The processing for mixture ratio estimation by a model corresponding to the covered background region, which corresponds to Step S402 in FIG. 68, will now be described with reference to the flowchart shown in FIG. 69.

[0578] In Step S421, the mixture ratio computation unit 423 obtains the pixel value C of the pixel of interest in the frame #n from the frame memory 421.

[0579] In Step S422, the mixture ratio computation unit 423 obtains the pixel value P of the pixel in the frame #n−1, which corresponds to the pixel of interest, from the frame memory 422.

[0580] In Step S423, the mixture ratio computation unit 423 obtains the pixel value N of the pixel in the frame #n+1, which corresponds to the pixel of interest contained in the input image.

[0581] In Step S424, the mixture ratio computation unit 423 computes the estimated mixture ratio based upon the pixel value C of the pixel of interest in the frame #n, the pixel value P of the pixel in the frame #n−1, and the pixel value N of the pixel in the frame #n+1.

[0582] In Step S425, the mixture ratio computation unit 423 judges whether or not the processing for computation of the estimated mixture ratio has been ended for the entire frame, and in the event that judgment is made that the processing for computation of the estimated mixture ratio has not been ended for the entire frame, the flow returns to Step S421, and the processing for calculating of the estimated mixture ratio is repeated for the following pixel.

[0583] In Step S425, in the event that judgment is made that the processing for computation of the estimated mixture ratio has been ended for the entire frame, the processing ends.

[0584] As described above, the estimated mixture ratio processing unit 401 can compute the estimated mixture ratio based upon the input image.

[0585] The processing of mixture ratio estimation by a model corresponding to the uncovered background region shown in Step S403 in FIG. 68 is the same as the processing indicated in the flowchart shown in FIG. 69, wherein expressions corresponding to a model of the uncovered background region are used, and accordingly description thereof will be omitted.

[0586] Note that the estimated mixture ratio processing unit 442 and the estimated mixture ratio processing unit 443 shown in FIG. 67 compute the estimated mixture ratio by performing the processing the same as the processing indicated in the flowchart shown in FIG. 69, and accordingly description thereof will be omitted.

[0587] Also, while description has been made with an assumption that the object corresponding to the background keeps still, the processing for obtaining the mixture ratio α described above may be applied even if the image corresponding to the background region contains movement. For example, in the event that the image corresponding to the background moves uniformly, the estimated mixture ratio processing unit 401 shifts the entire image corresponding to the background movement, and performs processing in the same manner as in the case wherein the object corresponding to the background keeps still. Also, in the event that the image corresponding to the background region contains the background movement which is different at each local position, the estimated mixture ratio processing unit 401 selects the pixels corresponding to the background movement as the pixels corresponding to the pixels belonging to the mixed region, and performs the processing described above.

[0588] Also, an arrangement may be made wherein the mixture ratio calculating unit 104 performs only the processing of the mixture ratio estimation by a model corresponding to the covered background region for all pixels, and outputs the calculated estimated mixture ratio as the mixture ratio α. In this case, the mixture ratio α indicates the ratio of the background components with regard to the pixels belonging to the covered background region, and indicates the ratio of the foreground components with regard to the pixels belonging to the uncovered background region. The image processing device can obtain the mixture ratio α indicating the ratio of the background components with regard to the pixels belonging to the uncovered background region, by calculating the absolute value of the difference between the mixture ratio α calculated as described above and 1, and setting the calculated absolute value for the mixture ratio α, with regard to the pixels belonging to the uncovered background region.

[0589] Note that similarly, an arrangement may be made wherein the mixture ratio calculating unit 104 performs only the processing for the mixture ratio estimation by a model corresponding to the uncovered background region for all pixels, and outputs the calculated estimated mixture ratio as the mixture ratio α.

[0590] Another processing of the mixture ratio calculation unit 104 will now be described.

[0591] An expression wherein the mixture ratio α and the sum of the foreground components f are approximated spatially can be formed, using the nature wherein the mixture ratio α changes linearly corresponding to the change of the pixel position due to the object corresponding to the foreground moving at a constant velocity within a shutter period. The mixture ratio α is calculated by solving the expression wherein the mixture ratio α and the sum of the foreground components f are approximated, using multiple sets of the pixel value of the pixel belonging to the mixed region and the pixel value of the pixel belonging to the background region.

[0592] In the event that the change of the mixture ratio α is generally linearly, the mixture ratio α is represented in Expression (23).
α=il+p  (23)

[0593] In Expression (23), i denotes the index in the spatial direction wherein the position of the pixel of interest is 0. l is the inclination of the straight line of the mixture ratio α. p is the intercept of the straight line of the mixture ratio α, as well as the mixture ratio α of the pixel of interest. In Expression (23), while the index i is known, the inclination l and the intercept p are unknown.

[0594] The correlation between the index i, the inclination l, and the intercept p, is shown in FIG. 70.

[0595] In FIG. 70 and FIG. 71, white circles indicate the pixel of interest. In FIG. 70, solid circles indicate pixels near the pixel of interest.

[0596] Multiple different mixture ratio α for multiple pixels are represented by two variables by approximating the mixture ratio α as in Expression (23). In the example shown in FIG. 70, five mixture ratios for five pixels are represented by two variables, i.e., the inclination l and the intercept p.

[0597] In the event of approximating the mixture ratio α in a planner manner shown in FIG. 71, taking the movement v corresponding to the two directions of the horizontal direction and the vertical direction of the image into consideration, the mixture ratio α is represented in Expression (24) by expanding Expression (23) onto a plane.
α=jm+kq+p  (24)

[0598] In Expression (24), j is the index in the horizontal direction wherein the position of the pixel of interest is 0, and k is the index in the vertical direction. m is the inclination of the mixture ratio α in the horizontal direction, and q is the inclination of the plane of the mixture ratio α in the vertical direction. p is the intercept of the plane of the mixture ratio α.

[0599] For example, in the frame #n shown in FIG. 61, Expression (25) through Expression (27) hold with regard to C05 through C07, respectively.
C05=α05·B05/v+f05  (25)
C06=α06·B06/v+f06  (26)
C07=α07·B07/v+f07  (27)

[0600] Making an assumption that the foreground components generally agree, i.e., that F01 through F03 are the same, and that F01 through F03 are written as Fc, Expression (28) holds.
f(x)=(1−α(x))·Fc  (28)

[0601] In Expression (28), x denotes the position in the spatial direction.

[0602] Rewriting α(x) as Expression (24), Expression (28) may be represented as Expression (29).

[0603] $\begin{array}{cc}\begin{array}{c}f\left(x\right)=\left(1-\left(\mathrm{jm}+\mathrm{kq}+p\right)\right)·\mathrm{Fc}\\ =j·\left(-m·\mathrm{Fc}\right)+k·\left(-q·\mathrm{Fc}\right)+\left(\left(1-p\right)·\mathrm{Fc}\right)\\ =\mathrm{js}+\mathrm{kt}+u\end{array}& \left(29\right)\end{array}$

[0604] In Expression (29), (−m·Fc), (−q·Fc), and (1−p)·Fc are rewritten as Expression (30) through Expression (32).
s=−m·Fc  (30)
t=−q·Fc  (31)
u=(1−p)·Fc  (32)

[0605] In Expression (29), j is the index in the horizontal direction wherein the position of pixel of interest is 0, and k is the index in the vertical direction.

[0606] As described above, since an assumption is made that the object corresponding to the foreground moves at a constant velocity within a shutter period, and the components corresponding to the foreground generally agree, the sum of the foreground components is approximated in Expression (29).

[0607] Note that in the event of approximating the mixture ratio α linearly, the sum of the foreground components may be represented in Expression (33).
f(x)=is+u  (33)

[0608] Rewriting the mixture ratio α and the sum of the foreground components in Expression (13) using Expression (24) and Expression (29), the pixel value M is represented in Expression (34).

[0609] $\begin{array}{cc}\begin{array}{c}M=\left(\mathrm{jm}+\mathrm{kq}+p\right)·B+\mathrm{js}+\mathrm{kt}+u\\ =\mathrm{jB}·m+\mathrm{kB}·q+B·p+j·s+k·t+u\end{array}& \left(34\right)\end{array}$

[0610] In Expression (34), the unknown variables are the six values of the inclination of the plane of the mixture ratio α in the horizontal direction, m, the inclination of the plane of the mixture ratio α in the vertical direction, q, the intercepts of the plane of the mixture ratio α, p, s, t, and u.

[0611] Setting the pixel value M and pixel value B for the normal equation represented in Expression (34) corresponding to the pixels near the pixel of interest, the mixture ratio α is calculated by solving multiple normal equations wherein the pixel value M and the pixel value B have been set, by the least square method.

[0612] For example, with the index j of the pixel of interest in the horizontal direction as 0, with the index k of the pixel of interest in the vertical direction as 0, and setting the pixel value M or the pixel value B for the normal equation represented in Expression (34) with regard to 3×3 pixels near the pixel of interest, Expression (35) through Expression (43) are obtained.
M_−1,−1=(−1)·B_−1,−1·m+(−1)·B_−1,−1·q+B_−1,−1·p+(−1)·s+(−1)·t+u  (35)
M_0,−1=(0)·B_0,−1·m+(−1)·B_0,−1·q+B_0,−1·p+(0)·s+(−1)·t+u  (36)
M_+1,−1=(+1)·B_+1,−1·m+(−1)·B_+1,−1·q+B_+1,−1·p+(+1)·s+(−1)·t+u  (37)
M_−1,0=(−1)·B_−1,0·m+(0)·B_−1,0·q+B_−1,0·p+(−1)·s+(0)·t+u  (38)
M_0,0=(0)·B_0,0·m+(0)·B_0,0·q+B_0,0·p+(0)·s+(0)·t+u  (39)
M_+1,0=(+1)·B_+1,0·m+(0)·B_+1,0·q+B_+1,0·p+(+1)·s+(0)·t+u  (40)
M_−1,+1=(−1)·B_−1,+1·m+(+1)·B_−1,+1·q+B_−1,+1·p+(−1)·s+(+1)·t+u  (41)
M_0,+1=(0)·B_0,+1·m+(+1)·B_0,+1·q+B_0,+1·p+(0)·s+(+1)·t+u  (42)
M_+1,+1=(+1)·B_+1,+1·m+(+1)·B_+1,+1·q+B_+1,+1·p+(+1)·s+(+1)·t+u  (43)

[0613] Since the index of the pixel of interest in the horizontal direction, j, is 0, and the index in the vertical direction, k, is 0, the mixture ratio α of the pixel of interest is equal to the value wherein j=0 and k=0, from Expression (24), i.e., the intercept p.

[0614] Accordingly, the intercept p can be output as the mixture ratio α by calculating the inclination in the horizontal direction, m, the inclination in the vertical direction, q, the intercept p, s, t, and u, by the least square method, based upon the nine expressions of Expression (35) through Expression (43).

[0615] More specific procedures for calculating the mixture ratio α by applying the least square method will now be described.

[0616] Representing the index i and the index k with one index x, the relationship between the index i, the index k, and the index x, is represented in Expression (44).
x=(j+1)·3+(k+1)  (44)

[0617] The inclination in the horizontal direction, m, the inclination in the vertical direction, q, the intercept p, s, t, and u, are represented by variables, w0, w1, w2, w3, w4, and w5, respectively, and jB, kB, B, j, k, and l are represented by a0, a1, a2, a3, a4, and a5, respectively. Taking the margin of error ex into consideration, Expression (35) through Expression (43) are rewritten as Expression (45).

[0618] $\begin{array}{cc}{M}_x=\sum _{y=0}^5\mathrm{ay}·\mathrm{wy}+\mathrm{ex}& \left(45\right)\end{array}$

[0619] In Expression (45), x denotes one of the integers between 0 and 8.

[0620] Expression (46) may be derived from Expression (45).

[0621] $\begin{array}{cc}{e}_x=M_x-\sum _{y=0}^5\mathrm{ay}·\mathrm{wy}& \left(46\right)\end{array}$

[0622] To apply the least square method, the sum of squares of margin of error E is defined as represented in Expression (47).

[0623] $\begin{array}{cc}E=\sum _{x=0}^8{\mathrm{ex}}^2& \left(47\right)\end{array}$

[0624] To minimize the margin of error, the partial derivative of the squared-sum of the margin of error E from the variable Wv should be 0. Here v is one of the integers between 0 through 5. Accordingly, wy is calculated so as to satisfy Expression (48).

[0625] $\begin{array}{cc}\begin{array}{c}\frac{\partial E}{\partial \mathrm{wv}}=2·\sum _{x=0}^8\mathrm{ex}·\frac{\partial \mathrm{ex}}{\partial \mathrm{wv}}\\ =2·\sum _{x=0}^8\mathrm{ex}·\mathrm{av}=0\end{array}& \left(48\right)\end{array}$

[0626] Substituting Expression (46) for Expression (48), Expression (49) is obtained.

[0627] $\begin{array}{cc}\sum _{x=0}^8(\mathrm{av}·\sum _{y=0}^5\mathrm{ay}·\mathrm{wy})=\sum _{x=0}^8\mathrm{av}·M_x& \left(49\right)\end{array}$

[0628] Applying, for example, the sweeping method (Gauss-Jordan elimination) and so forth, to the six expressions each of which is obtained by substituting-one of the integers between 0 and 5 for v in Expression (49), wy is calculated. As described above, w0 denotes the inclination in the horizontal direction, m, w1 denotes the inclination in the vertical direction, q, w2 denotes the intercept p, w3 denotes s, w4 denotes t, and w5 denotes u.

[0629] As described above, the inclination in the horizontal direction, m, the inclination in the vertical direction, q, the intercept p, s, t, and u may be obtained by applying the least square method to an expression wherein the pixel value M and the pixel value B have been set.

[0630] In the description corresponding to Expression (35) through Expression (43), while description has been made with the pixel value of the pixel included in the mixed region as M, and the pixel value of the pixel included in the background region as B, the normal equation needs to be formed for each case of the pixel of interest being included in the covered background region, and being included in the uncovered background region.

[0631] For example, in a case of obtaining the mixture ratio α of the pixel included in the covered background region of the frame #n shown in FIG. 61, the pixels of the frame #n, C04 through C08, and the pixel values of the pixels of the frame #n−1, P04 through P08, are set for the normal equation.

[0632] In a case of obtaining the mixture ratio α of the pixel included in the uncovered background region of the frame #n shown in FIG. 62, the pixels of the frame #n, C28 through C32, and the pixel values of the pixels of the frame #n+1, N28 through N32, are set for the normal equation.

[0633] Also, for example, in the event of calculating the mixture ratio α of the pixel included in the covered background region shown in FIG. 72, Expression (50) through Expression (58) shown below may be formed. The pixel value of the pixel for calculation of the mixture ratio α is Mc5.
Mc1=(−1)·Bc1·m+(−1)·Bc1·q+Bc1·p+(−1)·s+(−1)·t+u  (50)
Mc2=(0)·Bc2·m+(−1)·Bc2·q+Bc2·p+(0)·s+(−1)·t+u  (51)
Mc3=(+1)·Bc3·m+(−1)·Bc3·q+Bc3·p+(+1)·s+(−1)·t+u  (52)
Mc4=(−1)·Bc4·m+(0)·Bc4·q+Bc4·p+(−1)·s+(0)·t+u  (53)
Mc5=(0)·Bc5·m+(0)·Bc5·q+Bc5·p+(0)·s+(0)·t+u  (54)
Mc6=(+1)·Bc6·m+(0)·Bc6·q+Bc6·p+(+1)·s+(0)·t+u  (55)
Mc7=(−1)·Bc7·m+(+1)·Bc7·q+Bc7·p+(−1)·s+(+1)·t+u  (56)
Mc8=(0)·Bc8·m+(+1)·Bc8·q+Bc8·p+(0)·s+(1)·t+u  (57)
Mc9=(+1)·Bc9·m+(+1)·Bc9·q+Bc9·p+(+1)·s+(+1)·t+u  (58)

[0634] In the event of calculating the mixture ratio α of the pixel included in the covered background region in the frame #n, the pixel values Bc1 through Bc9 of the pixels in the background region in the frame #n−1 corresponding to the pixels in the frame #n, are used in Expression (50) through Expression (58).

[0635] In FIG. 72, white circles indicate the pixels which are regarded as backgrounds, and solid circles indicate the pixels which are regarded as pixels in the mixed region.

[0636] In the event of calculating the mixture ratio α of the pixel included in the uncovered background region shown in FIG. 72, Expression (59) through Expression (67) described below may be formed. The pixel value of the pixel for calculation of the mixture ratio α is Mu5.
Mu1=(−1)·Bu1·m+(−1)·Bu1·q+Bu1·p+(−1)·s+(−1)·t+u  (59)
Mu2=(0)·Bu2·m+(−1)·Bu2·q+Bu2·p+(0)·s+(−1)·t+u  (60)
Mu3=(+1)·Bu3·m+(−1)·Bu3·q+Bu3·p+(+1)·s+(−1)·t+u  (61)
Mu4=(−1)·Bu4·m+(0)·Bu4·q+Bu4·p+(−1)·s+(0)·t+u  (62)
Mu5=(0)·Bu5·m+(0)·Bu5·q+Bu5·p+(0)·s+(0)·t+u  (63)
Mu6=(+1)·Bu6·m+(0)·Bu6·q+Bu6·p+(+1)·s+(0)·t+u  (64)
Mu7=(−1)·Bu7·m+(+1)·Bu7·q+Bu7·p+(−1)·s+(+1)·t+u  (65)
Mu8=(0)·Bu8·m+(+1)·Bu8·q+Bu8·p+(0)·s+(1)·t+u  (66)
Mu9=(+1)·Bu9·m+(+1)·Bu9·q+Bu9·p+(+1)·s+(+1)·t+u  (67)

[0637] In the event of calculating the mixture ratio α of the pixel included in the uncovered background region in the frame #n, the pixel values Bu1 through Bu9 of the pixels in the background region in the frame #n+1 corresponding to the pixels in the frame #n, are used in Expression (59) through Expression (67).

[0638] FIG. 73 is a block diagram which illustrates the configuration of the estimated mixture ratio processing unit 401. The image input to the estimated mixture ratio processing unit 401 is supplied to a delay circuit 501 and an addition unit 502.

[0639] The delay circuit 501 delays the input image by one frame, and supplies to the addition unit 502. At the point that the frame #n is input to the addition unit 502 as an input image, the delay circuit 501 supplies the frame #n−1 to the addition unit 502.

[0640] The addition unit 502 sets the pixel values of the pixels near the pixel for calculation of the mixture ratio α, and the pixel values of the frame #n−1, for the normal equation. For example, the addition unit 502 sets the pixel values Mc1 through Mc9, and the pixel values Bc1 through Bc9 for the normal equation based upon Expression (50) through Expression (58). The addition unit 502 supplies the normal equation for which the pixel values have been set, to a computation unit 503.

[0641] The computation unit 503 obtains the estimated mixture ratio by solving the normal equation supplied from the addition unit 502 by the sweeping method or the like, and outputs the obtained estimated mixture ratio.

[0642] As described above, the estimated mixture ratio processing unit 401 can calculate the estimated mixture ratio based upon the input image, and supply to the mixture ratio decision unit 403.

[0643] Note that the estimated mixture ratio processing unit 402 has the same configuration as the estimated mixture ratio processing unit 401, and accordingly description thereof will be omitted.

[0644] FIG. 74 is a diagram which illustrates an example of the estimated mixture ratio calculated by the estimated mixture ratio processing unit 401. FIG. 74 illustrates the estimated mixture ratio with regard to one line, wherein the movement v of the foreground corresponding to the object which moves at a constant velocity is 11, and the results are calculated by the expression generated in increments of blocks 7×7 pixels.

[0645] It can be understood that the estimated mixture ratio changes generally linearly in the mixed region as shown in FIG. 60.

[0646] The mixture ratio decision unit 403 sets the mixture ratio based upon the region information indicating which of the foreground region, the background region, the covered background region, or the uncovered background region the pixel for calculation of the mixture ratio belongs to, supplied from the region specifying unit 101. In the event that the pixel which is the object belongs to the foreground region, the mixture ratio decision unit 403 sets the mixture ratio to 0, in the event that the pixel which is the object belongs to the background region, sets the mixture ratio to 1, in the event that the pixel which is the object belongs to the covered background region, sets the mixture ratio to the estimated mixture ratio supplied from the estimated mixture ratio processing unit 401, and in the event that the pixel which is the object belongs to the uncovered background region, sets the mixture ratio to the estimated mixture ratio supplied from the estimated mixture ratio processing unit 402. The mixture ratio decision unit 403 outputs the mixture ratio which is set based upon the region information.

[0647] Referring to the flowchart shown in FIG. 75, the processing for calculation of the mixture ratio by the mixture ratio calculating unit 102 in a case that the estimated mixture ratio processing unit 401 has a configuration shown in FIG. 73 will be described. In Step S501, the mixture ratio calculating unit 102 obtains the region information supplied from the region specifying unit 101. In Step S502, the estimated mixture ratio processing unit 401 performs the processing of mixture ratio estimation by a model corresponding to the covered background region, and supplies the estimated mixture ratio to the mixture ratio decision unit 403. Details of the processing for mixture ratio estimation will be described later with reference to the flowchart shown in FIG. 76.

[0648] In Step S503, the estimated mixture ratio processing unit 402 performs the processing of mixture ratio estimation by a model corresponding to the uncovered background region, and supplies the estimated mixture ratio to the mixture ratio decision unit 403.

[0649] In Step S504, the mixture ratio calculating unit 102 judges whether or not the mixture ratio has been estimated for the entire frame, and in the event that judgment is made that the mixture ratio has not been estimated for the entire frame, the flow returns to Step S502, and the processing of mixture ratio estimation for the following pixel is performed.

[0650] In Step S504, in the event that judgment is made that the mixture ratio has been estimated for the entire frame, the flow proceeds to Step S505, and the mixture ratio decision unit 403 sets the mixture ratio based upon the region information which indicates which of the foreground region, the background region, the covered background region, or the uncovered background region the pixel of calculation of the mixture ratio belongs to, supplied from the region specifying unit 101. In the event that the pixel which is the object belongs to the foreground region, the mixture ratio decision unit 403 sets the mixture ratio to 0, in the event that the pixel which is the object belongs to the background region, sets the mixture ratio to 1, in the event that the pixel which is the object belongs to the covered background region, sets the mixture ratio to the estimated mixture ratio supplied from the estimated mixture ratio processing unit 401, and in the event that the pixel which is the object belongs to the uncovered background region, sets the mixture ratio to the estimated mixture ratio supplied from the estimated mixture ratio processing unit 402, and processing ends.

[0651] As described above, the mixture ratio calculating unit 102 can calculate the mixture ratio α which is the amount of features corresponding to each pixel based upon the region information supplied from the region specifying unit 101 and the input image.

[0652] Using the mixture ratio α enables the separation of the foreground components and the background components contained in the pixel value while leaving the information of movement blurring contained in the image corresponding to the moving object.

[0653] Also, synthesizing an image based upon the mixture ratio α enables creation of an image containing accurate movement blurring corresponding to the speed of the object which moves as if image taking of the real world had been performed again.

[0654] The processing for the mixture ratio estimation by a model corresponding to the covered background region, which corresponds to Step S502 shown in FIG. 75, will now be described with reference to the flowchart shown in FIG. 76.

[0655] In Step S521, the addition unit 502 sets the pixel values contained in the input image and the pixels contained the image supplied from the delay circuit 501 for the normal equation corresponding to a model of the covered background region.

[0656] In Step S522, the estimated mixture ratio processing unit 401 judges whether or not setting of the pixel which is the object has ended, and in the event that judgment is made that the setting for the pixel which is the object has not ended, the flow returns to Step S521, and the processing of setting of the pixel value for the normal equation is repeated.

[0657] In Step S522, in the event that judgment is made that setting of pixel values with regard to the pixel which is the object has ended, the flow proceeds to Step S523, and the computation unit 503 computes the estimated mixture ratio based upon the normal equation which the pixel values have been set for, and outputs the obtained estimated mixture ratio.

[0658] As described above, the estimated mixture ratio processing unit 401 can computes the estimated mixture ratio based upon the input image.

[0659] The processing for mixture ratio estimation by a model corresponding to the uncovered background region in Step S153 shown in FIG. 75 is the same as the processing shown in the flowchart in FIG. 76 using the normal equation corresponding to a model of the uncovered background region, and accordingly, description thereof will be omitted.

[0660] Note that while description has been made with an assumption that the object corresponding to the background keeps still, the processing of obtaining the mixture ratio described above may be applied even if the image corresponding to the background contains movement. For example, in the event that the image corresponding to the background region moves uniformly, the estimated mixture ratio processing unit 401 shifts the entire image corresponding to the movement, and performs processing in the same manner as a case wherein the object corresponding to the background keeps still. Also, in the event that the image corresponding to the background contains different movement at each local position, the estimated mixture ratio processing unit 401 selects pixels corresponding to the movement as pixels corresponding to pixels belonging to the mixed region, and performs the above-described processing.

[0661] The foreground/background separation unit 105 will now be described. FIG. 77 is a block diagram which illustrates an example of the configuration of the foreground/background separation unit 105. The input image supplied to the foreground/background separation unit 105 is supplied to a separation unit 601, a switch 602, and a switch 603. The region information indicating the covered background region and the uncovered background region, which is supplied from the region specifying unit 103, is supplied to the separation unit 601. The region information indicating the foreground region is supplied to the switch 602. The region information indicating the background region is supplied to the switch 603.

[0662] The mixture ratio α supplied from the mixture ratio calculation unit 104 is supplied to the separation unit 601.

[0663] The separation unit 601 separates the background components from the covered background region in the input image, as well as foreground components, based upon the region information which indicates the covered background region and the mixture ratio α, and outputs the foreground component image in the covered background region which consists of the separated foreground components, and the background component image in the covered background region which consists of the separated background components.

[0664] The separation unit 601 separates the background components from the uncovered background region in the input image, as well as foreground components, based upon the region information which indicates the uncovered background region and the mixture ratio α, and outputs the foreground component image in the uncovered background region which consists of the separated foreground components, and the background component image in the uncovered background region which consists of the separated background components.

[0665] In the event of inputting the pixel corresponding to the foreground region, the switch 602 is closed based upon the region information which indicates the foreground region, and outputs the image in the foreground region.

[0666] In the event of inputting the pixel corresponding to the background region, the switch 603 is closed based upon the region information which indicates the background region, and outputs the image in the background region.

[0667] FIGS. 78A and FIG. 78B are diagrams which illustrate the input image input to the foreground/background separation unit 105, and the foreground component image and the background component image, output from the foreground/background separation unit 105.

[0668] FIG. 78A is a schematic diagram which illustrates the displayed image, and FIG. 78B is a model diagram wherein one line of pixels including pixels belonging to the foreground region, pixels belonging to the background region, and pixels belonging to the mixed region, corresponding to FIG. 78A, develop over the time direction.

[0669] As shown in FIGS. 78A and 78B, the image in the background region output from the foreground/background separation unit 105 is made up of pixels belonging to the background region.

[0670] As shown in FIGS. 78A and 78B, the image in the foreground region output from the foreground/background separation unit 105 is made up of pixels belonging to the foreground region.

[0671] The pixel value of the pixel in the uncovered background region is separated into the background components and the foreground components by the foreground/background separation unit 105. The separated background components make up the background component image in the uncovered background region, and the separated foreground components make up the foreground component image in the uncovered background region.

[0672] The pixel value of the pixel in the covered background region is separated into the background components and the foreground components by the foreground/background separation unit 105. The separated background components make up the background component image in the covered background region, and the separated foreground components make up the foreground component image in the covered background region.

[0673] A description will now be made regarding the separation processing for the foreground components and the background components from the pixel belonging to the mixed region performed by the separation unit 601.

[0674] FIG. 79 is a model of an image which indicates two frames of the foreground components and the background components, including the foreground corresponding to the object which moves from the left to the right in the drawing. In the model of the image shown in FIG. 79, the movement amount v of the foreground is 4, and the virtual dividing number is 4.

[0675] In the frame #n, the left-most pixel and the fourteenth through eighteenth pixels from the left are made up of only the background components, and belong to the background region. In the frame #n, the second through fourth pixels from the left are made up of the background components and the foreground components, and belong to the uncovered background region. In the frame #n, the eleventh through thirteenth pixels from the left are made up of the background components and the foreground components, and belong to the covered background region. In the frame #n, the fifth through tenth pixels from the left are made up of only the foreground components, and belong to the foreground region.

[0676] In the frame #n+1, the first through fifth pixels from the left and the eighteenth pixel from the left are made up of only the background components, and belong to the background region. In the frame #n+1, the sixth through eighth pixels from the left contain the background components and the foreground components, and belong to the uncovered background region. In the frame #n+1, the fifteenth through seventeenth pixels from the left contain the background components and the foreground components, and belong to the covered background region. In the frame #n+1, the ninth through fourteen pixels from the left are made up of only the foreground components, and belong to the foreground region.

[0677] FIG. 80 is a diagram which describes the processing for separation of the foreground components from the pixel belonging to the covered background region. In FIG. 80, α1 through α18 are the mixture ratios corresponding to the pixels in the frame #n, respectively. In FIG. 80, the fifteenth through seventeenth pixels from the left belong to the covered background region.

[0678] The pixel value C15 of the fifteenth pixel from the left in the frame #n is represented in Expression (68).

[0679] $\begin{array}{cc}\begin{array}{c}C15=B15/v+F09/v+F08/v+F07/v\\ =\mathrm{\alpha 15}·B15+F09/v+F08/v+F07/v\\ =\mathrm{\alpha 15}·P15+F09/v+F08/v+F07/v\end{array}& \left(68\right)\end{array}$

[0680] Here, α15 denotes the mixture ratio of the fifteenth pixel from the left in the frame #n. P15 denotes the pixel value of the fifteenth pixel from the left in the frame #n−1.

[0681] The sum f15 of the foreground components of the fifteenth pixel from the left in the frame #n is represented in Expression (69) based upon Expression (68).

[0682] $\begin{array}{cc}\begin{array}{c}f15=F09/v+F08/v+F07/v\\ =C15-\mathrm{\alpha 15}·P15\end{array}& \left(69\right)\end{array}$

[0683] Similarly, the sum f16 of the foreground components of the sixteenth pixel from the left in the frame #n is represented in Expression (70), and the sum f17 of the foreground components of the seventeenth pixel from the left in the frame #n is represented in Expression (71).
f16=C16−α16·P16  (70)
f17=C17−α17·P17  (71)

[0684] As described above, the foreground component fc contained in the pixel value C of the pixel belonging to the covered background region is calculated by Expression (72).
fc=C−α·P  (72)

[0685] P denotes the pixel value of the corresponding pixel in the previous frame.

[0686] FIG. 81 is a diagram which describes the processing for separating the foreground components from the pixel belonging to the uncovered background region. In FIG. 81, α1 through α18 denote the mixture ratio corresponding to the pixels in the frame #n, respectively. In FIG. 81, the second through fourth pixels from the left belong to the uncovered background region.

[0687] The pixel value C02 of the second pixel from the left in the frame #n is represented in Expression (73).

[0688] $\begin{array}{cc}\begin{array}{c}C02=B02/v+B02/v+B02/v+F01/v\\ =\mathrm{\alpha 2}·B02+F01/v\\ =\mathrm{\alpha 2}·N02+F01/v\end{array}& \left(73\right)\end{array}$

[0689] Here, α2 denotes the mixture ratio of the second pixel from the left in the frame #n. N02 denotes the pixel value of the second pixel from the left in the frame #n+1.

[0690] The foreground component sum of the second pixel from the left in the frame #n, f02, is represented in Expression (74) based upon Expression (73).

[0691] $\begin{array}{cc}\begin{array}{c}f02=F01/v\\ =C02-\mathrm{\alpha 2}·N02\end{array}& \left(74\right)\end{array}$

[0692] Similarly, the foreground component sum of the third pixel from the left in the frame #n, f03, is represented in Expression (75), and the foreground component sum of the fourth pixel from the left in the frame #n, f04, is represented in Expression (76).
f03=C03−α3·N03  (75)
f04=C04−α4·N04  (76)

[0693] As described above, the foreground component fu contained in the pixel value C of the pixel belonging to the uncovered background region is calculated by Expression (77).
fu=C−α·N  (77)

[0694] N denotes the pixel value of the corresponding pixel in the following frame.

[0695] As described above, the separation unit 601 can separate the foreground components and the background components from the pixel belonging to the mixed region based upon the information indicating the covered background region and the information indicating the uncovered background region, which is included in the region information, and the mixture ratio α for each pixel.

[0696] FIG. 82 is a block diagram which illustrates an example of the configuration of the separation unit 601 for performing the processing described above. The image input to the separation unit 601 is supplied to frame memory 621, and the region information indicating the covered background region and the uncovered background region supplied from the mixture ratio calculating unit 104, and the mixture ratio α is input to a separation processing block 622.

[0697] The frame memory 621 stores the input image in increments of frames. In the event that the object of processing is the frame #n, the frame memory 621 stores the frame #n−1 which is the frame previous to the frame #n, frame #n, and the frame #n+1 which is the frame following the frame #n.

[0698] The frame memory 621 supplies the corresponding pixels in the frame #n−1, the frame #n, and the frame #n+1 to the separation processing block 622.

[0699] The separation processing block 622 separates the foreground components and the background components from the pixel belonging to the mixed region in the frame #n by applying the computation described with reference to FIG. 80 and FIG. 81 to the pixel values of the pixels corresponding to the frame #n−1, the frame #n, and the frame #n+1 supplied from the frame memory 621 based upon the region information which indicates the covered background region and the uncovered background region and the mixture ratio α.

[0700] The separation processing block 622 comprises an uncovered region processing unit 631 and a covered region processing unit 632.

[0701] A multiplication device 641 of the uncovered region processing unit 631 multiplies the pixel value of the pixel of the frame #n+1 supplied from the frame memory 621 by the mixture ratio α, and outputs to a switch 642. In the event that the pixel (corresponding to the pixel in the frame #n+1) in the frame #n supplied from the frame memory 621 belongs to the uncovered background region, the switch 642 is closed, and supplies the pixel value multiplied by the mixture ratio α supplied from the multiplication device 641 to a computation device 643. The value wherein the pixel value of the pixel in the frame #n+1 is multiplied by the mixture ratio α supplied from the switch 642, is the same as the background component of the pixel value of the pixel corresponding to the frame #n, and is output as a background component image in the uncovered background region.

[0702] The computation device 643 obtains the foreground components by subtracting the background components supplied from the switch 642 from the pixel value of the pixel of the frame #n supplied from the frame memory 621. The computation device 643 outputs the foreground component image made up of pixels in the frame #n belonging to the uncovered background region.

[0703] A multiplication device 651 of the covered region processing unit 632 multiplies the pixel value of the pixel of the frame #n−1 supplied from the frame memory 621 by the mixture ratio α, and outputs to a switch 652. In the event that the pixel (corresponding to the pixel in the frame #n−1) in the frame #n supplied from the frame memory 621 belongs to the covered background region, the switch 652 is closed, and supplies the pixel value multiplied by the mixture ratio α supplied from the multiplication device 651 to a computation device 653. The value wherein the pixel value of the pixel in the frame #n−1 is multiplied by the mixture ratio α supplied from the switch 652, is the same as the background component of the pixel value of the corresponding pixel in the frame #n, and is output as a background component image in the covered background region.

[0704] The computation device 653 obtains the foreground components by subtracting the background components supplied from the switch 652 from the pixel value of the pixel of the frame #n supplied from the frame memory 621. The computation device 653 outputs the foreground component image made up of pixels in the frame #n belonging to the covered background region.

[0705] Using the mixture ratio α which is the amount of features enables entire separation of the foreground component and background component, contained in the pixel value.

[0706] The separation processing for the foreground and the background by the foreground/background separation unit 105 will now be described, with reference to the flowchart shown in FIG. 83. In Step S601, the frame memory 621 of the separation unit 601 obtains the input image, and stores the frame #n which is the object of the separation of the foreground and the background, as well as the previous frame #n−1 and the following frame #n+1.

[0707] In Step S602, the separation processing block 622 of the separation unit 601 obtains the region information supplied from the mixture ratio calculation unit 104. In Step S603, the separation processing block 622 of the separation unit 601 obtains the mixture ratio α supplied from the mixture ratio calculation unit 104.

[0708] In Step S604, the uncovered region processing unit 631 extracts the background components from the pixel value of the pixel belonging to the uncovered background region supplied from the frame memory 621 based upon the region information and the mixture ratio α, and outputs as the background component image in the uncovered background region.

[0709] In Step S605, the uncovered region processing unit 631 extracts the foreground components from the pixel value of the pixel belonging to the uncovered background region supplied from the frame memory 621 based upon the region information and the mixture ratio α, and outputs as the foreground component image in the uncovered background region.

[0710] In Step S606, the covered region processing unit 632 extracts the background components from the pixel value of the pixel belonging to the covered background region supplied from the frame memory 621 based upon the region information and the mixture ratio α, and outputs as the background component image in the covered background region.

[0711] In Step S607, the covered region processing unit 632 extracts the foreground components from the pixel value of the pixel belonging to the covered background region supplied from the frame memory 621 based upon the region information and the mixture ratio α, outputs as the foreground component image in the covered background region, and the processing ends.

[0712] As described above, the foreground/background separation unit 105 can separate the foreground components and the background components from the input image based upon the region information and the mixture ratio α, and output the foreground component image which is made up of only the foreground components, and the background component image which is made up of only the background components.

[0713] FIG. 84 is a block diagram which illustrates the configuration of the separated image processing unit 106 for generating a coefficient set which is used for the class classification adaptation processing for generating an even higher resolution image in the spatial direction. For example, the separated image processing unit 106 of which configuration is shown in FIG. 84 generates a coefficient set which is used for the class classification adaptation processing for generating an HD image from an SD image based upon the input HD image.

[0714] Background region tutor image frame memory 701 stores the image in the background region in the tutor image supplied from the foreground/background separation unit 105. The background region tutor image frame memory 701 supplies the stored image in the background region in the tutor image to a weighted averaging unit 707-1 and a learning unit 714-1.

[0715] Uncovered background region background component tutor image frame memory 702 stores the background component image in the uncovered background region in the tutor image supplied from the foreground/background separation unit 105. The uncovered background region background component tutor image frame memory 702 supplies the stored background component image in the uncovered background region in the tutor image to a weighted averaging unit 707-2 and a learning unit 714-2.

[0716] Uncovered background region foreground component tutor image frame memory 703 stores the foreground component image in the uncovered background region in the tutor image supplied from the foreground/background separation unit 105. The uncovered background region foreground component tutor image frame memory 703 supplies the stored foreground component image in the uncovered background region in the tutor image to a weighted averaging unit 707-3 and a learning unit 714-4.

[0717] Covered background region background component tutor image frame memory 704 stores the background component image in the covered background region in the tutor image supplied from the foreground/background separation unit 105. The covered background region background component tutor image frame memory 704 supplies the stored background component image in the covered background region in the tutor image to a weighted averaging unit 707-4 and a learning unit 714-4.

[0718] Covered background region foreground component tutor image frame memory 705 stores the foreground component image in the covered background region in the tutor image supplied from the foreground/background separation unit 105. The covered background region foreground component tutor image frame memory 705 supplies the stored foreground component image in the covered background region in the tutor image to a weighted averaging unit 707-5 and a learning unit 714-5.

[0719] Foreground region tutor image frame memory 706 stores the image in the foreground region in the tutor image supplied from the foreground/background separation unit 105. The foreground region tutor image frame memory 706 supplies the stored foreground image in the tutor image to a weighted averaging unit 707-6 and a learning unit 714-6.

[0720] The weighted averaging unit 707-1 generates an SD image which is a student image by ¼ weighted-averaging the image in the background region in the tutor image which is an HD image, for example, supplied from the background region tutor image frame memory 701, and supplies the generated SD image to background region student image frame memory 708.

[0721] For example, the weighted averaging unit 707-1 takes four pixels of 2×2 (width×height) (which are portions represented by white circles in the drawing) as one increment in the tutor image as shown in FIG. 85, adds the pixel values of four pixels in each increment, and the sum is divided by 4. The weighted averaging unit 707-1 sets the ¼ weighted averaged results described above for the pixel of the student image positioned at the center of each increment (which are the portions represented by solid circles in the drawing).

[0722] The background region student image frame memory 708 stores the student image corresponding to the image in the background region in the tutor image supplied from the weighted averaging unit 707-1. The background region student image frame memory 708 supplies the stored student image corresponding to the image in the background region in the tutor image to the learning unit 714-1.

[0723] The weighted averaging unit 707-2 generates an SD image which is a student image by ¼ weighted-averaging the background component image in the uncovered background region in the tutor image which is an HD image, for example, supplied from the uncovered background region background component tutor image frame memory 702, and supplies the generated SD image to uncovered background region background component student image frame memory 709.

[0724] The uncovered background region background component student image frame memory 709 stores the student image, which is an SD image, corresponding to the background component image in the uncovered background region in the tutor image supplied from the weighted averaging unit 707-2. The uncovered background region background component student image frame memory 709 supplies the stored student image corresponding to the background component image in the uncovered background region in the tutor image to the learning unit 714-2.

[0725] The weighted averaging unit 707-3 generates an SD image which is a student image by ¼ weighted-averaging the foreground component image in the uncovered background region in the tutor image which is an HD image, for example, supplied from the uncovered background region foreground component tutor image frame memory 703, and supplies the generated SD image to uncovered background region foreground component student image frame memory 710.

[0726] The uncovered background region foreground component student image frame memory 710 stores the student image, which is an SD image, corresponding to the foreground component image in the uncovered background region in the tutor image supplied from the weighted averaging unit 707-3. The uncovered background region foreground component student image frame memory 710 supplies the stored student image corresponding to the foreground component image in the uncovered background region in the tutor image to the learning unit 714-3.

[0727] The weighted averaging unit 707-4 generates an SD image, which is a student image, by ¼ weighted-averaging the background component image in the covered background region in the tutor image, for example, supplied from the covered background region background component tutor image frame memory 704, and supplies the generated SD image to covered background region background component student image frame memory 711.

[0728] The covered background region background component student image frame memory 711 stores the student image, which is an SD image, corresponding to the background component image in the covered background region in the tutor image supplied from the weighted averaging unit 707-4. The covered background region background component student image frame memory 711 supplies the stored student image corresponding to the background component image in the covered background region in the tutor image to the learning unit 714-4.

[0729] The weighted averaging unit 707-5 generates an SD image, which is a student image, by ¼ weighted-averaging the foreground component image in the covered background region in the tutor image, for example, supplied from the covered background region foreground component tutor image frame memory 705, and supplies the generated SD image to covered background region foreground component student image frame memory 712.

[0730] The covered background region foreground component student image frame memory 712 stores the student image, which is an SD image, corresponding to the foreground component image in the covered background region in the tutor image supplied from the weighted averaging unit 707-5. The covered background region foreground component student image frame memory 712 supplies the stored student image corresponding to the foreground component image in the covered background region in the tutor image to the learning unit 714-5.

[0731] The weighted averaging unit 707-6 generates an SD image which is a student image by ¼ weighted-averaging the image in the foreground region in the tutor image which is an HD image, for example, supplied from the foreground region tutor image frame memory 706, and supplies the generated SD image to foreground region student image frame memory 713.

[0732] The foreground region student image frame memory 713 stores the student image, which is an SD image, corresponding to the image in the foreground region in the tutor image supplied from the weighted averaging unit 707-6. The foreground region student image frame memory 713 supplies the stored student image corresponding to the image in the foreground region in the tutor image to the learning unit 714-6.

[0733] The learning unit 714-1 generates a coefficient set corresponding to the background region based upon the image in the background region in the tutor image supplied from the background region tutor image frame memory 701 and the student image corresponding to the image in the background region in the tutor image supplied from the background region student image frame memory 708, and supplies the generated coefficient set to coefficient set memory 715.

[0734] The learning unit 714-2 generates a coefficient set corresponding to the background component image in the uncovered background region based upon the background component image in the uncovered background region in the tutor image supplied from the uncovered background region background component tutor image frame memory 702 and the student image corresponding to the background component image in the uncovered background region in the tutor image supplied from the uncovered background region background component student image frame memory 709, and supplies the generated coefficient set to the coefficient set memory 715.

[0735] The learning unit 714-3 generates a coefficient set corresponding to the foreground component image in the uncovered background region based upon the foreground component image in the uncovered background region in the tutor image supplied from the uncovered background region foreground component tutor image frame memory 703 and the student image corresponding to the foreground component image in the uncovered background region in the tutor image supplied from the uncovered background region foreground component student image frame memory 909, and supplies the generated coefficient set to the coefficient set memory 715.

[0736] The learning unit 714-4 generates a coefficient set corresponding to the background component image in the covered background region based upon the background component image in the covered background region in the tutor image supplied from the covered background region background component tutor image frame memory 704 and the student image corresponding to the background component image in the covered background region in the tutor image supplied from the covered background region background component student image frame memory 711, and supplies the generated coefficient set to the coefficient set memory 715.

[0737] The learning unit 714-5 generates a coefficient set corresponding to the foreground component image in the covered background region based upon the foreground component image in the covered background region in the tutor image supplied from the covered background region foreground component tutor image frame memory 705 and the student image corresponding to the foreground component image in the covered background region in the tutor image supplied from the covered background region foreground component student image frame memory 712, and supplies the generated coefficient set to the coefficient set memory 715.

[0738] The learning unit 714-6 generates a coefficient set corresponding to the foreground region based upon the image in the foreground region in the tutor image supplied from the foreground region tutor image frame memory 706 and the student image corresponding to the image in the foreground region in the tutor image supplied from the foreground region student image frame memory 713, and supplies the generated coefficient set to the coefficient set memory 715.

[0739] The coefficient set memory 715 stores the coefficient set corresponding to the background region supplied from the learning unit 714-1, the coefficient set corresponding to the background component image in the uncovered background region supplied from the learning unit 714-2, the coefficient set corresponding to the foreground component image in the uncovered background region supplied from the learning unit 714-3, the coefficient set corresponding to the background component image in the covered background region supplied from the learning unit 714-4, the coefficient set corresponding to the foreground component image in the covered background region supplied from the learning unit 714-5, and the coefficient set corresponding to the foreground region supplied from the learning unit 714-6.

[0740] In the event that there is no need to differentiate between the learning unit 714-1 through the learning unit 714-6, individually, these will be simply referred to as a learning unit 714 below.

[0741] FIG. 86 is a block diagram which illustrates the configuration of the learning unit 714.

[0742] A class classification unit 731 comprises a class tap obtaining unit 751 and a waveform classification unit 752, and classifies the pixel of interest of the input student image. The class tap obtaining unit 751 obtains a predetermined number of class taps which are pixels of the student image corresponding to the pixel of interest, and supplies the obtained class taps to the waveform classification unit 752.

[0743] For example, in FIG. 85, in the event that the pixel which is the i'th from the top and the j'th from the left in the student image (which is a portion indicated by a solid circle in the drawing) is represented by X_ij, the class tap obtaining unit 751 obtains a class tap which consists of nine pixels in total, i.e., the eight pixels at left-top, right-top, left, right, bottom-left, bottom, and right-bottom, adjacent to the pixel of interest X_ij, X_{(i−1)(j−1)}, X_(i−1)j, X_(i−1)(j+1), X_i(j−1), X_i(j+1), X_{(i−1)(j−1)}, X_(i−1)j, and X_(i+1)(j+1), and also the pixel of interest. The class tap is supplied to the waveform classification unit 752.

[0744] Note that in this case, while the class tap consists of a square-shaped block made up of 3×3 pixels, this needs not be a square; rather other arbitrary shapes may be used, for example, a rectangle-shape, a cross-shape, or the like. Also, the number of pixels making up the class tap is not restricted to nine pixels of 3×3 pixels.

[0745] The waveform classification unit 752 performs class classification processing wherein the input signals are classified into several classes based upon the features thereof, and classifies the pixel of interest into one class based upon the class taps. For example, the waveform classification unit 752 classifies the pixel of interest into one of 512 classes, and supplies the class No. corresponding to the classified class to a prediction tap obtaining unit 732.

[0746] Here, the class classification processing will now be described briefly.

[0747] Now, let us say that a given pixel of interest and three adjacent pixels make up a class tap which consists of 2×2 pixels as shown in FIG. 87A, and each pixel is represented by 1 bit (has a level of either 0 or 1). In FIG. 87A, the solid circle denotes the pixel of interest. In this case, four pixel block of 2×2 pixels containing the pixel of interest can be classified into 16(=(2¹)⁴) patterns by the level distribution for each pixel as shown in FIG. 87B. In FIG. 87B, white circles denote 0, and solid circles denote 1. Accordingly, in this case, the pixel of interest can be classified into sixteen patterns, wherein pattern-classification is the class-classification processing, and the processing is performed by the class classification unit 731.

[0748] Here, each pixel is generally appropriated around 8 bits. Also, with the present embodiment, the class tap consists of nine pixels of 3×3 pixels as described above. Accordingly, performing class classification processing for such a class tap as an object, the class tap would result the class tap being classified into a great number of classes of which number is (2⁸)⁹.

[0749] Accordingly, with the present embodiment, the ADCR processing is performed for the class tap by the waveform classification unit 752, and this reduces the number of classes by reducing the number of bits of the pixels making up the class tap.

[0750] In order to simplify description, the maximum value of the pixel value MAX and the minimum value of the pixel value MIN are detected in the ADRC processing with a class tap which consists of four pixels arrayed in a line as shown in FIG. 88A. DR=MAX−MIN is then taken as the local dynamic range in the block which consists of a class tap, and the pixel values of the pixels making up the block of the class tap is re-quantized into K bits based upon the dynamic range DR.

[0751] That is to say, the minimum value MIN is subtracted from each pixel value within the block, and the subtraction value is divided by DR/2^k. The division value obtained as a result is converted into the code (ADRC code) corresponding thereto. Specifically, for example, in the event of taking K as 2, judgment is made which of ranges obtained by dividing the dynamic range DR into four (=2²) equal parts the division value belongs to, as shown in FIG. 88B, and upon the division value belonging to the range of the bottom-most level, the range of the second level from the bottom, the range of the third level from the bottom, or the range of upper-most level, the division value is encoded into 2-bit code such as 00B, 01B, 10B, or 11B (B indicates a binary number), respectively, for example. Decoding is then performed on the decoding side by the ADRC code 00B, 01B, 10B, or 11B being converted into the median in the range of the most-bottom level L₀₀, the median in the range of the second level from the bottom L₀₁, the median in the range of the third level from the bottom L₁₀, or the median in the range of the most-upper level L₁₁, wherein the ranges are obtained by dividing the dynamic range DR into four equal parts, and the minimum value MIN being added to the converted value.

[0752] Here, the ADRC processing described above is referred to as non-edge-matching.

[0753] Note that details with regard to the ADRC processing are disclosed in Japanese Unexamined Patent Application Publication No. 3-53778, which has been applied by the present applicant, and so forth, for example.

[0754] The class No. can be reduced by performing the ADRC processing which performs re-quantizing with the number of bits less than the number of bits appropriated to pixels making up the class tap as described above, and the ADRC processing described above is performed by the waveform classifying unit 752.

[0755] While the class classification processing is performed based upon the ADRC code by the waveform classification unit 752 in the present embodiment, an arrangement may be made wherein the class classification processing is performed with regard to the data which has been subjected to DPCM (Predictive Coding), BTC (Block Truncation Coding), VQ (Vector Quantizing), DCT (Disperse Cosine Transformation), Hadamard transformation, or the like.

[0756] The prediction tap obtaining unit 732 obtains the prediction tap which is the increment for calculation of the predicted value of the original image (tutor image) corresponding to the class based upon the class No. from pixels of the student image, and supplies the obtained prediction tap and the class No. to a corresponding pixel obtaining unit 733.

[0757] For example, in FIG. 85, let us say that pixel values of nine pixels of 2×2 centered on the pixel X_ij in the student image (which is denoted by a solid circle in the drawing) in the original image (tutor image) are represented as Y_ij(1), Y_ij(2), Y_ij(3), and Y_ij(4), respectively, in the direction from the far left to the right, and in the direction from the top to the bottom, the prediction tap obtaining unit 732 obtains a square-shaped prediction tap which consists of nine pixels of 3×3, X_{(i−1)(j−1)}, X_(i−1)j, X_(i−1)(j+1) X_i(j−1), X_ij, X_i(j+1), X_(i+1)(j−1), X_(i+1)j, and X_(i+1)(j+1), centered on the pixel X_ij in the student image, for example, for calculating the coefficients which are necessary for calculation of the predicted values of the pixels Y_ij(1) through Y_ij(4).

[0758] Specifically, for example, the pixels X₂₂, X₂₃, X₂₄, X₃₂, X₃₃, X₃₄, X₄₂, X₄₃, and X₄₄ make up the prediction tap for calculating the coefficients which are necessary for calculation of the predicted values of four pixels of Y₃₃(1) through Y₃₃(4) in the tutor image, which are enclosed by a quadrangle in FIG. 85, (in this case, the pixel of interest is X₃₃).

[0759] The corresponding pixel obtaining unit 733 obtains pixel values of the pixels in the tutor image corresponding to the pixel values which are to be predicted based upon the prediction tap and the class No., and supplies the prediction tap, the class No., and the obtained pixel values of the pixels in the tutor image corresponding to the pixel values which are to be predicted to a normal equation generating unit 734.

[0760] For example, in the event of calculating the coefficients necessary for calculation of the predicted values of four pixels of Y₃₃(1) through Y₃₃(4) in the tutor image, the corresponding pixel obtaining unit 733 obtains the pixel values of the pixels, Y₃₃(1) through Y₃₃(4) as the pixels in the tutor image corresponding to the pixel values which are to be predicted.

[0761] The normal equation generating unit 734 generates normal equations for calculating a coefficient set which is used in the adaptation processing, corresponding to the correlation between the prediction tap and the pixel values which are to be predicted, based upon the prediction tap, the class No., and the obtained pixel values which are to be predicted, and supplies the generated normal equations to a coefficient calculation unit 735 along with the class No.

[0762] The coefficient calculation unit 735 calculates a coefficient set which is used in the adaptation processing, corresponding to the classified class, by solving the normal equations supplied from the normal equation generating unit 734. The coefficient calculation unit 735 supplies the calculated coefficient set to the coefficient set memory 715 along with the class No.

[0763] An arrangement may be made wherein the normal equation generating unit 734 generates a matrix corresponding to such normal equations, and the coefficient calculation unit 735 calculates a coefficient set based upon the generated matrix.

[0764] Here, the adaptation processing will be described.

[0765] For example, let us now consider obtaining predicted value E[y] of the pixel value y in the tutor image from a linear one-dimensional combination model defined by linear combination of pixel values of several nearby pixels x₁, x₂, . . . (which will be referred to as student data as appropriate) and predetermined prediction coefficients w₁, w₂, . . . . In this case, the predicted value E[y] may be represented in the following Expression.
E[y]=w₁x₁+w₂x₂+  (78)

[0766] Accordingly, for generalization, upon defining the matrix W which consists of a set of the prediction coefficients w, the matrix X which consists of a set of the student data, and the matrix Y′ which consists of a set of the predicted values E[y] as

[0767] $\begin{array}{c}X=\left[\begin{array}{cccc}{x}_{11}& x_{12}& \dots & x_{1n}\\ x_{21}& x_{22}& \dots & x_{2n}\\ \dots & \dots & \dots & \dots \\ x_{m1}& x_{m2}& \dots & x_{mn}\end{array}\right]\\ W=\left[\begin{array}{c}{w}_1\\ w_2\\ \dots \\ w_n\end{array}\right],\\ Y^{\prime }=\left[\begin{array}{c}E\left[y_1\right]\\ E\left[y_2\right]\\ \dots \\ E\left[y_m\right]\end{array}\right],\end{array}$
the following observation expression holds.
XW=Y′  (79)

[0768] Let us now consider obtaining the predicted value E[y] near the pixel value y of the original image by applying the least square method to the observation expression. In this case, upon defining the matrix Y which consists of a set of pixel values y in the original image (which will be referred to as tutor data as appropriate) and the matrix E which consists of a set of the residuals e of the predicted values E[y] with regard to the pixel values y in the original image as

[0769] $E=\left(\begin{array}{c}{e}_1\\ e_2\\ \dots \\ e_m\end{array}\right),Y=\left(\begin{array}{c}{y}_1\\ y_2\\ \dots \\ y_m\end{array}\right),$
the following residual expression holds from Expression (79).
XW=Y+E  (80)

[0770] In this case, the prediction coefficients w_i for obtaining the predicted value E[y] near the pixel value y in the original image can be obtained by minimizing the squared margin of error

[0771] $\sum _{i=1}^m{e}_i^2.$

[0772] Accordingly, in a case that the derivative of the above-described squared margin of error from the prediction coefficient w_i is 0, that is to say, in a case that the prediction coefficient w_i satisfies the following expression, the prediction coefficient w_i is the optimal value for obtaining the predicted values E[y] near the pixel value y in the original image.

[0773] $\begin{array}{cc}{e}_1\frac{\partial e_1}{\partial w_i}+e_2\frac{\partial e_2}{\partial w_i}+\dots +e_m\frac{\partial e_m}{\partial w_i}=0\left(i=1,2,\dots ,n\right)& \left(81\right)\end{array}$

[0774] Here, the following expression holds by differentiating Expression (80) by the prediction coefficient w_i.

[0775] $\begin{array}{cc}\frac{\partial e_i}{\partial w_1}=x_{i1},\frac{\partial e_i}{\partial w_2}=x_{i2},\dots \frac{\partial e_i}{\partial w_n}=x_{\mathrm{in}},\left(i=1,2,\dots ,m\right)& \left(82\right)\end{array}$

[0776] Expression (83) is obtained from Expression (81) and Expression (82).

[0777] $\begin{array}{cc}\sum _{i=1}^m{e}_i{x}_{i1}=0,\sum _{i=1}^m{e}_i{x}_{i2}=0,\dots \sum _{i=1}^m{e}_i{x}_{\mathrm{in}}=0& \left(83\right)\end{array}$

[0778] Moreover, taking the relationship between the student data x, the prediction coefficient w, the tutor data y, and the residuals e in the residual expression (80), into consideration, the following normal equations can be obtained from Expression (83).

[0779] $\begin{array}{cc}\{\begin{array}{c}\left(\sum _{i=1}^m{x}_{i1}{x}_{i1}\right)w_1+\left(\sum _{i=1}^m{x}_{i1}{x}_{i2}\right)w_2+\dots +\left(\sum _{i=1}^m{x}_{i1}{x}_{\mathrm{in}}\right)w_n=\left(\sum _{i=1}^m{x}_{i1}{y}_i\right)\\ \left(\sum _{i=1}^m{x}_{i2}{x}_{i1}\right)w_1+\left(\sum _{i=1}^m{x}_{i2}{x}_{i2}\right)w_2+\dots +\left(\sum _{i=1}^m{x}_{i2}{x}_{\mathrm{in}}\right)w_n=\left(\sum _{i=1}^m{x}_{i2}{y}_i\right)\\ \dots \\ \left(\sum _{i=1}^m{x}_{in}{x}_{i1}\right)w_1+\left(\sum _{i=1}^m{x}_{in}{x}_{i2}\right)w_2+\dots +\left(\sum _{i=1}^m{x}_{in}{x}_{in}\right)w_n=\left(\sum _{i=1}^m{x}_{\mathrm{in}}{y}_i\right)\end{array}& \left(84\right)\end{array}$

[0780] As many normal equations represented in Expression (84) can be formed as the number of the prediction coefficients w which are to be obtained, and accordingly the optimal prediction coefficients w can be obtained by solving Expression (84). Note that Expressions (84) can be solved by applying the sweeping method (Gauss-Jordan elimination), for example.

[0781] The adaptation processing consists of the optimal prediction coefficients w being obtained for each class, and the predicted values E[y] near the pixel values y in the tutor image being obtained by Expression (78) using the prediction coefficients w.

[0782] The normal equation generating unit 734 generates the normal equations for calculating the optimal prediction coefficients w for each class, and the coefficient calculation unit 735 calculates the prediction coefficients w based upon the generated normal equations.

[0783] Note that the adaptation processing is different from the interpolation processing with regard to the components which are not contained in the thinned out image and are contained in the original image being reproduced. That is to say, while in the event of taking only Expression (78) into consideration, the adaptation processing is the same as the interpolation processing using the interpolation filter, the prediction coefficients w corresponding to the tap coefficients of the interpolation filter is obtained by learning as if it were, using the tutor data y, and accordingly the adaptation processing can reproduce the components contained in the original image. Accordingly, it can be said that the adaptation processing acts to create an image, as if it were.

[0784] FIG. 89 is a diagram which describes a coefficient set generated by the separated image processing unit 106 of which configuration is shown in FIG. 84. The region specifying unit 103 specifies the foreground region, the background region, the covered background region, and the uncovered background region in the input image.

[0785] The input image wherein the regions have been specified and the mixture ratio α has been detected by the mixture ratio calculation unit 104, is separated into the image in the foreground region, the image in the background region, the foreground component image in the covered background region, the background component image in the covered background region, the foreground component image in the uncovered background region, and the background component image in the uncovered background region, by the foreground/background separation unit 105.

[0786] The separated image processing unit 106 calculates a coefficient set corresponding to the image in the foreground region, a coefficient set corresponding to the image in the background region, a coefficient set corresponding to the foreground component image in the covered background region, a coefficient set corresponding to the background component image in the covered background region, a coefficient set corresponding to the foreground component image in the uncovered background region, and a coefficient set corresponding to the background component image in the uncovered background region individually, based upon the separated images, i.e., the image in the foreground region, image in the background region, foreground component image in the covered background region, background component image in the covered background region, foreground component image in the uncovered background region, and background component image in the uncovered background region.

[0787] That is to say, the learning unit 714-1 calculates a coefficient set corresponding to the background region based upon the separated image in the background region, the learning unit 714-2 calculates a coefficient set corresponding to the background component image in the uncovered background region based upon the separated background component image in the uncovered background region, the learning unit 714-3 calculates a coefficient set corresponding to the foreground component image in the uncovered background region based upon the separated foreground component image in the uncovered background region, the learning unit 714-4 calculates a coefficient set corresponding to the background component image in the covered background region based upon the separated background component image in the covered background region, the learning unit 714-5 calculates a coefficient set corresponding to the foreground component image in the covered background region based upon the separated foreground component image in the covered background region, and the learning unit 714-6 calculates a coefficient set corresponding to the foreground region based upon the separated image in the foreground region.

[0788] The coefficient set corresponding to the background region is used for prediction of the pixel value in the background region in the class classification adaptation processing for predicting pixel values. The coefficient set corresponding to the background component image in the uncovered background region is used for prediction of the pixel value corresponding to the background component image in the uncovered background region in the class classification adaptation processing for predicting pixel values. The coefficient set corresponding to the foreground component image in the uncovered background region is used for prediction of the pixel value corresponding to the foreground component image in the uncovered background region in the class classification adaptation processing for predicting pixel values.

[0789] The coefficient set corresponding to the background component image in the covered background region is used for prediction of the pixel value corresponding to the background component image in the covered background region in the class classification adaptation processing for predicting pixel values. The coefficient set corresponding to the foreground component image in the covered background region is used for prediction of the pixel value corresponding to the foreground component image in the covered background region in the class classification adaptation processing for predicting pixel values.

[0790] The coefficient set corresponding to the foreground region is used for prediction of the pixel value in the foreground region in the class classification adaptation processing for predicting pixel values.

[0791] The predicted image corresponding to the image in the background region, the predicted image corresponding to the background component image in the uncovered background region, the predicted image corresponding to the foreground component image in the uncovered background region, the predicted image corresponding to the background component image in the covered background region, the predicted image corresponding to the foreground component image in the covered background region, and the predicted image corresponding to the image in the foreground region, are synthesized into a single predicted image.

[0792] Referring to the flowchart shown in FIG. 90, description will be made with regard to the processing of learning for generating a coefficient set which is used for prediction of pixel values based upon the class classification adaptation processing by the separated image processing unit 106 of which configuration is shown in FIG. 84.

[0793] In Step S701, the weighted averaging units 707-1 through 707-6 generate a student images of the image in the background region, the image in the foreground region, the background component image in the uncovered background region, the foreground component image in the uncovered background region, the background component image in the covered background region, and the foreground component image in the covered background region. That is to say, the weighted averaging unit 707-1 generates a student image corresponding to the image in the background region in the tutor image by ¼ weighted-averaging of the image in the background region in the tutor image stored in the background region tutor image frame memory 701, for example.

[0794] The weighted averaging unit 707-2 generates a student image corresponding to the background component image in the uncovered background region in the tutor image by ¼ weighted-averaging of the background component image in the uncovered background region in the tutor image stored in the uncovered background region background component tutor image frame memory 702, for example.

[0795] The weighted averaging unit 707-3 generates a student image corresponding to the foreground component image in the uncovered background region in the tutor image by ¼ weighted-averaging of the foreground component image in the uncovered background region in the tutor image stored in the uncovered background region foreground component tutor image frame memory 703, for example.

[0796] The weighted averaging unit 707-4 generates a student image corresponding to the background component image in the covered background region in the tutor image by ¼ weighted-averaging of the background component image in the covered background region in the tutor image stored in the covered background region background component tutor image frame memory 704, for example.

[0797] The weighted averaging unit 707-5 generates a student image corresponding to the foreground component image in the covered background region in the tutor image by ¼ weighted-averaging of the foreground component image in the covered background region in the tutor image stored in the covered background region foreground component tutor image frame memory 705, for example.

[0798] The weighted averaging unit 707-6 generates a student image corresponding to the image in the foreground region in the tutor image by ¼ weighted-averaging of the image in the foreground region in the tutor image stored in the foreground region tutor image frame memory 706, for example.

[0799] In Step S702, the learning unit 714-1 generates a coefficient set corresponding to the background region based upon the image in the background region in the tutor image stored in the background region tutor image frame memory 701 and the student image corresponding to the image in the background region in the tutor image stored in the background region student image frame memory 708. Details of the processing for generating of a coefficient set in Step S702 will be described later with reference to the flowchart shown in FIG. 91.

[0800] In Step S703, the learning unit 714-2 generates a coefficient set corresponding to the background component image in the uncovered background region based upon the background component image in the uncovered background region in the tutor image stored in the uncovered background region background component tutor image frame memory 702 and the student image corresponding to the background component image in the uncovered background region in the tutor image stored in the uncovered background region background component student image frame memory 709.

[0801] In Step S704, the learning unit 714-3 generates a coefficient set corresponding to the foreground component image in the uncovered background region based upon the foreground component image in the uncovered background region in the tutor image stored in the uncovered background region foreground component tutor image frame memory 703 and the student image corresponding to the foreground component image in the uncovered background region in the tutor image stored in the uncovered background region foreground component student image frame memory 710.

[0802] In Step S705, the learning unit 714-4 generates a coefficient set corresponding to the background component image in the covered background region based upon the background component image in the covered background region in the tutor image stored in the covered background region background component tutor image frame memory 704 and the student image corresponding to the background component image in the covered background region in the tutor image stored in the covered background region background component student image frame memory 711.

[0803] In Step S706, the learning unit 714-5 generates a coefficient set corresponding to the foreground component image in the covered background region based upon the foreground component image in the covered background region in the tutor image stored in the covered background region foreground component tutor image frame memory 705 and the student image corresponding to the foreground component image in the covered background region in the tutor image stored in the covered background region foreground component student image frame memory 712.

[0804] In Step S707, the learning unit 714-6 generates a coefficient set corresponding to the foreground region based upon the image in the foreground region in the tutor image stored in the foreground region tutor image frame memory 706 and the student image corresponding to the image in the foreground region in the tutor image stored in the foreground region student image frame memory 713.

[0805] In Step S708, the learning units 714-1 through the learning unit 712-4 output a coefficient set corresponding to the background region, a coefficient set corresponding to the background component image in the uncovered background region, a coefficient set corresponding to the foreground component image in the uncovered background region, a coefficient set corresponding to the background component image in the covered background region, a coefficient set corresponding to the foreground component image in the covered background region, or a coefficient set corresponding to foreground region, to the coefficient set memory 715, respectively. The coefficient set memory 715 stores the coefficient sets each of which corresponds to the background region, the foreground region, the background component image in the uncovered background region, the foreground component image in the uncovered background region, the background component image in the covered background region, and the foreground component image in the covered background region, and then the processing ends.

[0806] As described above, the separated image processing unit 106 of which configuration is shown in FIG. 84 can generate a coefficient set corresponding to the image in the background region, a coefficient set corresponding to the background component image in the uncovered background region, a coefficient set corresponding to the foreground component image in the uncovered background region, a coefficient set corresponding to the background component image in the covered background region, a coefficient set corresponding to the foreground component image in the covered background region, and a coefficient set corresponding to the image in the foreground region.

[0807] Note that it is needless to say that the processing in Step S702 through Step S707 may be performed serially or in parallel.

[0808] Referring to the flowchart shown in FIG. 91, the processing for generating of a coefficient set corresponding to the background region performed by the learning unit 714-1, corresponding to the processing in Step S702, will now be described.

[0809] In Step S721, the learning unit 714-1 judges whether or not there are any unprocessed pixels in the student image corresponding to the background region, and in the event that judgment is made that there are unprocessed pixels in the student image corresponding to the background region, the flow proceeds to Step S722, and the pixel of interest is obtained from the student image corresponding to the background region in raster scan sequence.

[0810] In Step S723, the class tap obtaining unit 751 of the class classification unit 731 obtains a class tap corresponding to the pixel of interest from the student image stored in the background region student image frame memory 708. In Step S724, the waveform classification unit 752 of the class classification unit 731 applies the ADRC processing to the class tap, this reduces the number of bits of pixels making up the class tap, and the pixel of interest is classified. In Step S725, the prediction tap obtaining unit 732 obtains a prediction tap corresponding to the pixel of interest from the student image stored in the background region student image frame memory 708 based upon the classified class.

[0811] In Step S726, the corresponding pixel obtaining unit 733 obtains pixels corresponding to the pixel value which is to be predicted from the background region image of the tutor image stored in the background region tutor image frame memory 701 based upon the classified class.

[0812] In Step S727, the normal equation generating unit 734 adds the pixel values of pixels corresponding to the prediction tap and the pixel value which is to be predicted to the matrix for each class based upon the classified class, the flow returns to Step S721, and the separated image processing unit 106 repeats judgment whether or not unprocessed pixels exist. The prediction tap and the matrix for each class to which the pixel values of pixels corresponding to the prediction tap and the pixel value which is to be predicted is added, corresponds to the normal equations for calculating a coefficient set for each class.

[0813] In Step S721, in the event that judgment is made that there are no unprocessed pixels in the student image, the flow proceeds to Step S728, and the normal equation generating unit 734 supplies the matrix for each class for which the pixel values of the pixels corresponding to the prediction tap and the pixel value which is to be predicted are set, to the coefficient calculation unit 735. The coefficient calculation unit 735 calculates a coefficient set for each class corresponding to the background region by solving the matrix for each class, wherein the pixel values of pixels corresponding to the prediction tap and the pixel value which is to be predicted are set.

[0814] Note that the coefficient set is not restricted to predicting the pixel values by linear prediction, rather, an arrangement may be made wherein the coefficient calculation unit 735 calculates a coefficient set for predicting the pixel values by non-linear prediction.

[0815] In Step S729, the coefficient calculation unit 735 outputs the coefficient set for each class, corresponding to the background region to the coefficient set memory 715, and the processing ends.

[0816] As described above, the learning unit 714-1 can generate a coefficient set corresponding to the background region.

[0817] The processing for generating the coefficient set corresponding to the background component image in the uncovered background region by the learning unit 714-2 corresponding to Step S703 is the same as the processing described with reference to the flowchart shown in FIG. 91 except for using the background component image in the uncovered background region stored in the uncovered background region background component tutor image frame memory 702 and the student image corresponding to the background component image in the uncovered background region stored in the uncovered background region background component student image frame memory 709, and accordingly, description thereof will be omitted.

[0818] The processing for generating of the coefficient set corresponding to the foreground component image in the uncovered background region by the learning unit 714-3 corresponding to Step S704 is the same as the processing described with reference to the flowchart shown in FIG. 91 except for using the foreground component image in the uncovered background region stored in the uncovered background region foreground component tutor image frame memory 703 and the student image corresponding to the foreground component image in the uncovered background region stored in the uncovered background region foreground component student image frame memory 710, and accordingly, description thereof will be omitted.

[0819] The processing for generating of the coefficient set corresponding to the background component image in the covered background region by the learning unit 714-4 corresponding to Step S705 is the same as the processing described with reference to the flowchart shown in FIG. 91 except for using the background component image in the covered background region stored in the covered background region background component tutor image frame memory 704 and the student image corresponding to the background component image in the covered background region stored in the covered background region background component student image frame memory 711, and accordingly, description thereof will be omitted.

[0820] The processing for generating of the coefficient set corresponding to the foreground component image in the covered background region by the learning unit 714-5 corresponding to Step S706 is the same as the processing described with reference to the flowchart shown in FIG. 91 except for using the foreground component image in the covered background region stored in the covered background region foreground component tutor image frame memory 705 and the student image corresponding to the foreground component image in the covered background region stored in the covered background region foreground component student image frame memory 712, and accordingly, description thereof will be omitted.

[0821] The processing for generating of the coefficient set corresponding to the foreground region by the learning unit 714-6 corresponding to Step S707 is the same as the processing described with reference to the flowchart shown in FIG. 91 except for using the image in the foreground region stored in the foreground region tutor image frame memory 706 and the student image corresponding to the image in the foreground region stored in the foreground region student image frame memory 713, and accordingly, description thereof will be omitted.

[0822] As described above, the separated image processing unit 106 of which configuration is shown in FIG. 84 can generate a coefficient set corresponding to the background region, a coefficient set corresponding to the background component image in the uncovered background region, a coefficient set corresponding to the foreground component image in the uncovered background region, a coefficient set corresponding to the background component image in the covered background region, a coefficient set corresponding to the foreground component image in the covered background region, and a coefficient set corresponding to the foreground region, individually.

[0823] FIG. 92 is a block diagram which illustrates the configuration of the separated image processing unit 106 for generating an even higher resolution image in the spatial direction by performing the class classification adaptation processing. For example, the separated image processing unit 106 of which configuration is shown in FIG. 92 generates an HD image by performing the class classification processing based upon the input image which is an SD image.

[0824] Background region frame memory 801 stores the image in the background region made up of pixels belonging to the background region supplied from the foreground/background separation unit 105. The background region frame memory 801 supplies the stored image in the background region to a mapping unit 807-1.

[0825] Uncovered background region background component image frame memory 802 stores the background component image in the uncovered background region supplied from the foreground/background separation unit 105. The uncovered background region background component image frame memory 802 supplies the stored background component image in the uncovered background region to a mapping unit 807-2.

[0826] Uncovered background region foreground component image frame memory 803 stores the foreground component image in the uncovered background region supplied from the foreground/background separation unit 105. The uncovered background region foreground component image frame memory 803 supplies the stored foreground component image in the uncovered background region to a mapping unit 807-3.

[0827] Covered background region background component image frame memory 804 stores the background component image in the covered background region supplied from the foreground/background separation unit 105. The covered background region background component image frame memory 804 supplies the stored background component image in the covered background region to a mapping unit 807-4.

[0828] Covered background region foreground component image frame memory 805 stores the foreground component image in the covered background region supplied from the foreground/background separation unit 105. The covered background region foreground component image frame memory 805 supplies the stored foreground component image in the covered background region to a mapping unit 807-5.

[0829] Foreground region frame memory 806 stores the image in the foreground region made up of pixels belonging to the foreground region supplied from the foreground/background separation unit 105. The foreground region image frame memory 806 supplies the stored image in the foreground region to a mapping unit 807-6.

[0830] The mapping unit 807-1 generates a predicted image corresponding to the image in the background region stored in the background region frame memory 801 by the class classification adaptation processing based upon the coefficient set corresponding to the background region stored in coefficient set memory 808. The mapping unit 807-1 supplies the generated predicted image to a synthesizing unit 809.

[0831] The mapping unit 807-2 generates a predicted image corresponding to the background component image in the uncovered background region stored in the uncovered background region background component image frame memory 802 by the class classification adaptation processing based upon the coefficient set corresponding to the background component image in the uncovered background region stored in the coefficient set memory 808. The mapping unit 807-2 supplies the generated predicted image to the synthesizing unit 809.

[0832] The mapping unit 807-3 generates a predicted image corresponding to the foreground component image in the uncovered background region stored in the uncovered background region foreground component image frame memory 803 by the class classification adaptation processing based upon the coefficient set corresponding to the foreground component image in the uncovered background region stored in the coefficient set memory 808. The mapping unit 807-3 supplies the generated predicted image to the synthesizing unit 809.

[0833] The mapping unit 807-4 generates a predicted image corresponding to the background component image in the covered background region stored in the covered background region background component image frame memory 804 by the class classification adaptation processing based upon the coefficient set corresponding to the background component image in the covered background region stored in the coefficient set memory 808. The mapping unit 807-4 supplies the generated predicted image to the synthesizing unit 809.

[0834] The mapping unit 807-5 generates a predicted image corresponding to the foreground component image in the covered background region stored in the covered background region foreground component image frame memory 805 by the class classification adaptation processing based upon the coefficient set corresponding to the foreground component image in the covered background region stored in the coefficient set memory 808. The mapping unit 807-5 supplies the generated predicted image to the synthesizing unit 809.